Composition containing carbon nanotubes having a coating

ABSTRACT

The object of the present invention is to provide a carbon nanotube composition that does not impair the characteristics of the carbon nanotubes itself, allows the carbon nanotubes to be dispersed or solubilized in a solvent, does not cause separation or aggregation of the carbon nanotubes even during long-term storage, has superior electrical conductivity, film formability and moldability, can be easily coated or covered onto a base material, and the resulting coated film has superior moisture resistance, weather resistance and hardness; a composite having a coated film composed thereof; and, their production methods. In order to achieve this object, the present invention provides a carbon nanotube composition that contains a conducting polymer (a) or heterocyclic compound trimer (i), a solvent (b) and carbon nanotubes (c), and may additionally contain a high molecular weight compound (d), a basic compound (e), a surfactant (f), a silane coupling agent (g) and colloidal silica (h) as necessary; a composite having a coated film composed of the composition; and, their production methods.

This Application is the National Phase of International Application No.PCT/JP03/14027 filed Oct. 31, 2003, and claims the priority fromJapanese Application Nos. JP 2002-319551 filed Nov. 1, 2002, JP2002-319552 filed Nov. 1, 2002, JP 2003-311926 filed Sep. 3, 2003, JP2003-311927 filed Sep. 3, 2003, and JP 2003-367533 filed Oct. 28, 2003,the complete disclosures of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a carbon nanotube composition, acomposite having a coated film composed of the same, and theirproduction methods.

BACKGROUND ART

Ever since carbon nanotubes were first discovered by Iijima, et al. in1991 (S. Iijima, Nature, 354, 56 (1991)), their physical properties havebeen evaluated and their functions have been elucidated, and extensiveresearch and development have been conducted on their application.However, since carbon nanotubes are produced in an entangled state, theyhave the shortcoming of being extremely bothersome to handle. In thecase of mixing into resins and solutions, there is also the problem ofthe carbon nanotubes becoming increasingly aggregated, therebypreventing them from demonstrating their inherent characteristics.

Consequently, attempts have been made to uniformly disperse orsolubilize carbon nanotubes in solvents or resins by subjecting them tophysical treatment or chemical modification.

For example, a method has been proposed in which single-walled carbonnanotubes are cut into short pieces and dispersed by subjecting toultrasonic treatment in strong acid (R. E. Smalley, et al., Science,280, 1253 (1998)). However, since treatment is carried out in strongacid, the procedure is complex and not suitable for industrialapplications, while the dispersion effects cannot be said to beadequate.

Therefore, by noticing that both ends of single-walled carbon nanotubescut in the manner proposed above are open, and that they are terminatedwith oxygen-containing functional groups such as carboxylic acid groups,it was proposed that carbon nanotubes be made soluble in solvent byintroducing long-chain alkyl groups by reacting with an amine compoundafter having converted the carboxylic acid groups into acid chloride (J.Chen, et al., Science, 282, 95 (1998)). However, in this method, sincelong-chain alkyl groups are introduced into single-walled carbonnanotubes by covalent bonding, there was still the problem of damage tothe graphene sheet structure of the carbon nanotubes and effects on thecharacteristics of the carbon nanotubes itself.

Another attempt to produce water soluble single-walled carbon nanotubeswas reported that comprising introducing substituents containingammonium ions in pyrene molecules by utilizing the fact that pyrenemolecules are adsorbed onto the surfaces of carbon nanotubes by stronginteraction, and subjecting these to ultrasonic treatment in watertogether with single-walled carbon nanotubes to non-covalently adsorbthem to the single-walled carbon nanotubes (Nakajima, et al., Chem.Lett., 638 (2002)). According to this method, although damage to thegraphene sheet structure is inhibited due to the non-covalent bondingchemical modification, since non-conducting pyrene compounds arepresent, there is the problem of a decrease in the conductivity of theresulting carbon nanotubes.

DISCLOSURE OF THE INVENTION

The object of the present invention is to provide a carbon nanotubecomposition that does not impair the characteristics of the carbonnanotubes itself, allows the carbon nanotubes to be dispersed orsolubilized in water, organic solvents, water-containing organicsolvents and other solvents, does not cause separation or aggregation ofthe carbon nanotubes even during long-term storage, has superiorelectrical conductivity, film formability and moldability, can be easilycoated or covered onto a base material, and the resulting coated filmhas superior moisture resistance, weather resistance and hardness. Theobject of the present invention is also to provide a composite having acoated film comprising the carbon nanotube composition as well asproduction methods of the carbon nanotube composition and the coatedfilm.

As a result of extensive research to solve these problems, the inventorof the present invention found that carbon nanotubes can be dispersed orsolubilized in solvent by placing in the presence of a conductingpolymer, thereby leading to completion of the present invention.

Namely, a first aspect of the present invention is a carbon nanotubecomposition that contains a conducting polymer (a), a solvent (b) andcarbon nanotubes (c).

In the carbon nanotube composition of this first aspect of the presentinvention, since the carbon nanotubes (c) are added to the solvent (b)together with the conducting polymer (a), the carbon nanotubes (c) canbe dispersed or solubilized in the solvent (b) without impairing thecharacteristics of the carbon nanotubes (c) itself, and there is noseparation or aggregation even during long-term storage. Although thereason for this is not fully understood, the carbon nanotubes (c) arepresumed to be dispersed or solubilized together with the conductingpolymer (a) due to mutual adsorption by the conducting polymer (a) andthe carbon nanotubes (c) due to the π-π interaction by π electrons.

In addition, in the carbon nanotube composition of the presentinvention, since the conducting polymer (a) and the carbon nanotubes (c)are used in combination, the resulting composition has superiorelectrical conductivity, film formability and moldability.

The performance of the carbon nanotube composition can be improved byadditionally containing a high molecular weight compound (d), a basiccompound (e), a surfactant (f) and a silane coupling agent (g) and/or acolloidal silica (h).

In addition, the conducting polymer (a) is preferably a water solubleconducting polymer, and more preferably a water soluble conductingpolymer having at least one of a sulfonic acid group and a carboxylgroup.

Moreover, as a result of extensive research to solve the aforementionedproblems, the inventor of the present invention found that a compositioncontaining a heterocyclic compound trimer and carbon nanotubes issuitable for this purpose, thereby leading to the present invention.

Namely, a second aspect of the present invention is a carbon nanotubecomposition that contains a heterocyclic compound trimer (i), a solvent(b) and carbon nanotubes (c). Similar to the carbon nanotube compositionof the first aspect of the present invention, performance of thecomposition can be improved by additionally containing a high molecularweight compound (d), a basic compound (e), a surfactant (f), a silanecoupling agent (g) and/or a colloidal silica (h).

The carbon nanotube compositions of the first and second aspects of thepresent invention enable the carbon nanotubes to be dispersed orsolubilized in water, an organic solvent and a water-containing organicsolvent without impairing the characteristics of the carbon nanotubesitself, and there is no separation or aggregation even during long-termstorage. In addition, according to the carbon nanotube composition ofthe present invention, a coated film having superior electricalconductivity and film formability can be obtained free of temperaturedependence by coating the composition onto a base material and allowingthe coated film to demonstrate the characteristics of a conductingpolymer, a heterocyclic compound trimer having a sulfonic acid group anda carboxyl group or carbon nanotubes itself. Moreover, the resultingcoated film has superior moisture resistance, weather resistance andhardness.

A third aspect of the present invention is a production method of acarbon nanotube composition comprising mixing a conducting polymer (a)or a heterocyclic compound trimer (i), a solvent (b) and carbonnanotubes (c), and irradiating with ultrasonic waves. The carbonnanotubes can be efficiently dispersed or solubilized in the solvent bythis ultrasonic treatment.

A fourth aspect of the present invention is a composite having a coatedfilm composed of a carbon nanotube composition of the present inventionon at least one surface of a base material.

In addition, a fifth aspect of the present invention is a productionmethod of a composite comprising coating a carbon nanotube compositionof the present invention onto at least one surface of a base material,and forming a coated film by allowing to stand at an ordinarytemperature or subjecting to heating treatment.

BEST MODE FOR CARRYING OUT THE INVENTION

The following provides a detailed explanation of the present invention.

<Conducting Polymer (a)>

Conducting polymer (a) is a π-conjugated polymer containing as itsrepeating unit phenylene vinylene, vinylene, thienylene, pyrollylene,phenylene, iminophenylene, isothianaphthene, furylene or carbazolyleneand so forth.

With respect to solubility in solvent in particular, a so-called watersoluble conducting polymer is used preferably in the present invention.Here, a water soluble conducting polymer refers to a conducting polymerthat has acidic groups, alkyl groups substituted with acidic groups oralkyl groups containing ether bonds on the backbone of a n-conjugatedpolymer or on nitrogen atoms of the polymer.

In addition, among these water soluble conducting polymers, a watersoluble conducting polymer having at least one of a sulfonic acid groupand a carboxyl group is used preferably in the present invention withrespect to solubility in solvent, electrical conductivity and filmformability.

Water soluble conducting polymers, disclosed in, for example, JapaneseUnexamined Patent Application, First Publication No. S61-197633,Japanese Unexamined Patent Application, First Publication No. S63-39916,Japanese Unexamined Patent Application, First Publication No.H01-301714, Japanese Unexamined Patent Application, First PublicationNo. H05-504153, Japanese Unexamined Patent Application, FirstPublication No. H05-503953, Japanese Unexamined Patent Application,First Publication No. H04-32848, Japanese Unexamined Patent Application,First Publication No. H04-328181, Japanese Unexamined PatentApplication, First Publication No. H06-145386, Japanese UnexaminedPatent Application, First Publication No. H06-56987, Japanese UnexaminedPatent Application, First Publication No. H05-226238, JapaneseUnexamined Patent Application, First Publication No. H05-178989,Japanese Unexamined Patent Application, First Publication No.H06-293828, Japanese Unexamined Patent Application, First PublicationNo. H07-118524, Japanese Unexamined Patent Application, FirstPublication No. H06-32845, Japanese Unexamined Patent Application, FirstPublication No. H06-87949, Japanese Unexamined Patent Application, FirstPublication No. H06-256516, Japanese Unexamined Patent Application,First Publication No. H07-41756, Japanese Unexamined Patent Application,First Publication No. H07-48436, Japanese Unexamined Patent Application,First Publication No. H04-268331, Japanese Unexamined PatentApplication, First Publication No. H09-59376, Japanese Unexamined PatentApplication, First Publication No. 2000-191774, Japanese UnexaminedPatent Application, Japanese Unexamined Patent Application, FirstPublication No. H06-49183 and Japanese Unexamined Patent Application,First Publication No. H10-60108, are preferably used as a water solubleconducting polymer having at least one of a sulfonic acid group and acarboxyl group.

Specific examples of a water soluble conducting polymers having at leastone of a sulfonic acid group and a carboxyl group include water solubleconducting polymers having at least one of a sulfonic acid group and acarboxyl group, an alkyl group substituted with at least one of asulfonic acid group and a carboxyl group, or an alkyl group containingan ether bond, on the backbone of a π-conjugated polymer or nitrogenatoms of the polymer that contains as its repeating unit at least onetype selected from the group consisting of non-substituted orsubstituted phenylene vinylene, vinylene, thienylene, pyrollylene,phenylene, iminophenylene, isothianaphthene, furylene and carbazolylene.In particular, among these, a water soluble conducting polymer having abackbone that contains thienylene, pyrollylene, iminophenylene,phenylene vinylene, carbazolylene or isothianaphthene is usedpreferably.

Preferable water soluble conducting polymers having at least one of asulfonic acid group and a carboxyl group are the water solubleconducting polymers that contain 20 to 100% of at least one type of therepeating units selected from the following formulas (2) to (10)relative to the total number of repeating units throughout the entirepolymer:

(in-the structural formula (2), wherein R¹ and R² are respectively andindependently selected from the group consisting of H, —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —OCH₃, —CH₃, —C₂H₅, —F, —Cl, —Br, —I, —N(R³⁵)₂,—NHCOR³⁵, —OH, —O⁻, —SR³⁵, —OR³⁵, —OCOR³⁵, —NO₂, —COOH, —R³⁵COOH,—COOR³⁵, —COR³⁵, —CHO, and —CN, where R³⁵ represents an alkyl, aryl, oraralkyl group having 1 to 24 carbon atoms or an alkylene, arylene, oraralkylene group having 1 to 24 carbon atoms, and at least one of R¹ andR² is a group selected from the group consisting of —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —COOH and —R³⁵COOH);

(in the structural formula (3), wherein R³ and R⁴ are respectively andindependently selected from the group consisting of H, —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —OCH₃, —CH₃, —C₂H₅, —F, —Cl, —Br, —I, —N(R³⁵)₂,—NHCOR³⁵, —OH, —O⁻, —SR³⁵, —OR³⁵, —OCOR³⁵, —NO₂, —COOH, —R³⁵COOH,—COOR³⁵, —COR³⁵, —CHO, and —CN, where R³⁵ represents an alkyl, aryl, oraralkyl group having 1 to 24 carbon atoms or an alkylene, arylene, oraralkylene group having 1 to 24 carbon atoms, and at least one of R³ andR⁴ is a group selected from the group consisting of —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —COOH and —R³⁵COOH);

(in the structural formula (4), wherein R⁵ to R⁸ are respectively andindependently selected from the group consisting of H, —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —OCH₃, —CH₃, —C₂H₅, —F, —Cl, —Br, —I, —N(R³⁵)₂,—NHCOR³⁵, —OH, —O⁻, —SR³⁵, —OR³⁵, —OCOR³⁵, —NO₂, —COOH, —R³⁵COOH,—COOR³⁵, —COR³⁵, —CHO and —CN, where R³⁵ represents an alkyl, aryl, oraralkyl group having 1 to 24 carbon atoms or an alkylene, arylene, oraralkylene group having 1 to 24 carbon atoms, and at least one of R⁵ toR⁸ is a group selected from the group consisting of —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —COOH and —R³⁵COOH);

(in the structural formula (5), wherein R⁹ to R¹³ are respectively andindependently selected from the group consisting of H, —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —OCH₃, —CH₃, —C₂H₅, —F, —Cl, —Br, —I, —N(R³⁵)₂,—NHCOR³⁵, —OH, —O⁻, —SR³⁵, —OR³⁵, —OCOR³⁵, —NO₂, —COOH, —R³⁵COOH,—COOR³⁵, —COR³⁵, —CHO, and —CN, where R³⁵ represents an alkyl, aryl, oraralkyl group having 1 to 24 carbon atoms or an alkylene, arylene oraralkylene group having 1 to 24 carbon atoms, and at least one of R⁹ toR¹³ is a group selected from the group consisting of —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —COOH and —R³⁵COOH);

(in the structural formula (6),wherein R¹⁴ is selected from the groupconsisting of —SO₃ ⁻, —SO₃H, —R⁴²SO₃ ⁻, —R⁴²SO₃H, —COOH, and —R⁴²COOH,where R⁴² represents an alkylene, arylene or aralkylene group having 1to 24 carbon atoms);

(in the structural formula (7), wherein R⁵² to R⁵⁷ are respectively andindependently selected from the group consisting of H, —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —OCH₃, —CH₃, —C₂H₅, —F, —Cl, —Br, —I, —N(R³⁵)₂,—NHCOR³⁵, —OH, —O⁻, —SR³⁵, —OR³⁵, —OCOR³⁵, —NO₂, —COOH, —R³⁵COOH,—COOR³⁵, —COR³⁵, —CHO, and —CN, where R³⁵ represents an alkyl, aryl oraralkyl grouphaving 1 to 24 carbon atoms or an alkylene, arylene oraralkylene group having 1 to 24 carbon atoms, at least one of R⁵² to R⁵⁷is a group selected from the group consisting of —SO₃ ⁻, —SO₃H, —R³⁵SO₃⁻, —R³⁵SO₃H, —COOH, and —R³⁵COOH, Ht represents a heteroatom groupselected from the group consisting of NR⁸², S, O, Se, and Te, where R⁸²represents hydrogen or a linear or branched alkyl group having 1 to 24carbon atoms or substituted or non-substituted aryl group having 1 to 24carbon atoms, the hydrocarbon chains of R⁵² to R⁵⁷ mutually bond atarbitrary locations and may form a bivalent chain that forms at leastone cyclic structure of saturated or unsaturated hydrocarbons of a 3 to7-member ring together with the carbon atoms substituted by the groups,the cyclic bonded chain formed in this manner may contain a carbonyl,ether, ester, amide, sulfide, sulfinyl, sulfonyl or imino bond atarbitrary locations, and n represents the number of condensed ringssandwiched between a hetero ring and a benzene ring having substituentsR⁵³ to R⁵⁶, and is 0 or an integer of 1 to 3);

(in the structural formula (8), wherein R⁵⁸ to R⁶⁶ are respectively andindependently selected from the group consisting of H, —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —OCH₃, —CH₃, —C₂H₅, —F, —Cl, —Br, —I, —N(R³⁵)₂,—NHCOR³⁵, —OH, —O⁻, —SR³⁵, —OR³⁵, —OCOR³⁵, —NO₂, —COOH, —R³⁵COOH,—COOR³⁵, —COR³⁵, —CHO, and —CN, where R³⁵ represents an alkyl, aryl oraralkyl group having 1 to 24 carbon atoms or an alkylene, arylene oraralkylene group having 1 to 24 carbon atoms, at least one of R⁵⁸ to R⁶⁶is a group selected from the group consisting of —SO₃ ⁻, —SO₃H, —R³⁵SO₃⁻, —R³⁵SO₃H, —COOH, and —R³⁵COOH, and n represents the number ofcondensed rings sandwiched between a benzene ring having substituentsR⁵⁸ and R⁵⁹ and a benzene ring having substituents R⁶¹ to R⁶⁴, and is 0or an integer of 1 to 3);

(in the structural formula (9), wherein R⁶⁷ to R⁷⁶ are respectively andindependently selected from the group consisting of H, —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —OCH₃, —CH₃, —C₂H₅, —F, —Cl, —Br, —I, —N(R³⁵)₂,—NHCOR³⁵, —OH, —O⁻, —SR³⁵, —OR³⁵, —OCOR³⁵, —NO₂, —COOH, —R³⁵COOH,—COOR³⁵, —COR³⁵, —CHO, and —CN, where R³⁵ represents an alkyl, aryl oraralkyl group having 1 to 24 carbon atoms or an alkylene, arylene oraralkylene group having 1 to 24 carbon atoms, at least one of R⁶⁷ to R⁷⁶is a group selected from the group consisting of —SO₃ ⁻, —SO₃H, —R³⁵SO₃⁻, —R³⁵SO₃H, —COOH, and —R³⁵COOH, and n represents the number ofcondensed rings sandwiched between a benzene ring having substituentsR⁶⁷ to R⁶⁹ and a benzoquinone ring, and is 0 or an integer of 1 to 3);and,

(in the structural formula (10), wherein R⁷⁷ to R⁸¹ are respectively andindependently selected from the group consisting of H, —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —OCH₃, —CH₃, —C₂H₅, —F, —Cl, —Br, —I, —N(R³⁵)₂,—NHCOR³⁵, —OH, —O⁻, —SR³⁵, —OR³⁵, —OR³⁵, —OCOR³⁵, —NO₂, —COOH, —R³⁵COOH,—COOR³⁵, —COR³⁵, —CHO, and —CN, where R³⁵ represents an alkyl, aryl oraralkyl group having 1 to 24 carbon atoms or an alkylene, arylene oraralkylene group having 1 to 24 carbon atoms, at least one of R⁷⁷ to R⁸¹is a group selected from the group consisting of —SO₃ ⁻, —SO₃H, —R³⁵SO₃⁻, —R³⁵SO₃H, —COOH, and —R³⁵COOH, X^(a−) is at least one type of anionselected from the group of anions having a valence of 1 to 3 consistingof a chlorine ion, bromine ion, iodine ion, fluorine ion, nitrate ion,sulfate ion, hydrogensulfate ion, phosphate ion, borofluoride ion,perchlorate ion, thiocyanate ion, acetate ion, propionate ion, methanesulfonate ion, p toluene sulfonate ion, trifluoroacetate ion, andtrifluoromethane sulfonate ion, a represents the ion valence of X and isan integer of 1 to 3, and p represents the doping ratio and has a valueof 0.001 to 1).

In addition, polyethylene dioxythiophene polystyrene sulfate is alsoused as a preferable water soluble conducting polymer having at leastone of a sulfonic acid group and a carboxyl group. Although this watersoluble conducting polymer does not have any sulfonic acid groupsintroduced into the backbone of the conducting polymer, it has astructure in which polystyrene sulfonate is added as a dopant. Thispolymer can be produced by polymerizing 3,4-ethylene dioxythiophene(Bayer, Baytron M) with an oxidizing agent such as iron toluenesulfonate (Bayer, Baytron C). In addition, this polymer can also beacquired in the form of Baytron P (Bayer).

An even more preferable water soluble conducting polymer having at leastone of a sulfonic acid group and a carboxyl group is a water solubleconducting polymer that contains 20 to 100% of the repeating unitrepresented by the following formula (11) relative to the total numberof repeating units throughout the entire polymer:

(in the structural formula (11), wherein y represents an arbitrarynumber such that 0<y<1, R¹⁵ to R³² are respectively and independentlyselected from the group consisting of H, —SO₃ ⁻, —SO₃H, —R³⁵SO₃ ⁻,—R³⁵SO₃H, —OCH₃, —CH₃, —C₂H₅, —F, —Cl, —Br, —I, —N(R³⁵)₂, —NHCOR³⁵, —OH,—O⁻, —SR³⁵, —OR³⁵, —OCOR³⁵, —NO₂, —COOH, —R³⁵COOH, —COOR³⁵, —COR³⁵,—CHO, and —CN, where R³⁵ represents an alkyl, aryl or aralkyl grouphaving 1 to 24 carbon atoms or an alkylene, arylene or aralkylene grouphaving 1 to 24 carbon atoms, and at least one of R¹⁵ to R³² is a groupselected from the group consisting of —SO₃ ⁻, —SO₃H, —R³⁵SO₃ ⁻,—R³⁵SO₃H, —COOH and —R³⁵COOH).

Here, a water soluble conducting polymer in which the content ofrepeating units having at least one of a sulfonic acid group and acarboxyl group is 50% or more relative to the total number of repeatingunits of the polymer is used preferably since it has extremely favorablesolubility in solvents such as water and water-containing organicsolvents. The content of repeating units having at least one of asulfonic acid group and a carboxyl group is more preferably 70% or more,even more preferably 90% or more, and particularly preferably 100%.

In addition, a substituent added to the aromatic ring is preferably analkyl group, alkoxy group or halogen group, from the perspective ofelectrical conductivity and solubility, and water soluble conductingpolymers having an alkoxy group are the most preferable. The mostpreferable water soluble conducting polymer among these combinations isshown in the following formula (12):

(in the structural formula (12), wherein R³³ represents one groupselected from the group consisting of a sulfonic acid group, carboxylgroup, their alkaline metal salts, ammonium salts and substitutedammonium salts, R³⁴ represents one group selected from the groupconsisting of a methyl group, ethyl group, n-propyl group, iso-propylgroup, n-butyl group, iso-butyl group, sec-butyl group, tert-butylgroup, dodecyl group, tetracosyl group, methoxy group, ethoxy group,n-propoxy group, iso-butoxy group, sec-butoxy group, tert-butoxy group,heptoxy group, hexoxy group, octoxy group, dodecoxy group, tetracoxygroup, fluoro group, chloro group and bromo group, X represents anarbitrary number such that 0<X<1, and n represents the degree ofpolymerization and has a value of 3 or more).

Here, at least a portion of R³³ is preferably at least one of a sulfonicacid group and a carboxyl group of a free acid from the perspective ofimproving electrical conductivity.

Polymers obtained by various types of synthesis methods such as chemicalpolymerization or electrolytic polymerization can be used for a watersoluble conducting polymer in the present invention. For example,synthesis methods described in Japanese Unexamined Patent Application,First Publication No. H7-196791 and Japanese Unexamined PatentApplication, First Publication No. H7-324132 proposed by the inventorsof the present invention can be applied. Namely, this refers to watersoluble conducting polymers obtained by polymerizing at least one of theacidic group-substituted aniline represented by the following formula(13), its alkaline metal salt, ammonium salt and substituted ammoniumsalt, with an oxidizing agent in a solution containing a basic compound:

(in the structural formula (13), wherein R³⁶ to R⁴¹ are respectively andindependently selected from the group consisting of H, —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —OCH₃, —CH₃, —C₂H₅, —F, —Cl, —Br, —I, —N(R³⁵)₂,—NHCOR³⁵, —OH, —O⁻, —SR³⁵, —OR³⁵, —OCOR³⁵, —NO₂, —COOH, —R³⁵COOH,—COOR³⁵, —COR³⁵, —CHO, and —CN, where R³⁵ represents an alkyl, aryl oraralkyl group having 1 to 24 carbon atoms or an alkylene, arylene oraralkylene group having 1 to 24 carbon atoms, and at least one of R³⁶ toR is a group selected from the group consisting of —SO₃ ⁻, —SO₃H,—R³⁵SO₃ ⁻, —R³⁵SO₃H, —COOH and —R³⁵COOH).

A particularly preferable water soluble conducting polymer is a watersoluble conducting polymer obtained by polymerizing at least one type ofalkoxy group-substituted aminobenzene sulfonic acid, its alkaline metalsalt, ammonium salt and substituted ammonium salt, with an oxidizingagent in a solution containing a basic compound.

At least a portion of the acidic groups contained in a water solubleconducting polymer in the present invention are preferably in the formof free acid from the viewpoint of improving electrical conductivity. Inaddition, a water soluble conducting polymer in the present inventionhaving a mass average molecular weight as GPC polyethylene of 2,000 to3,000,000 is used preferably due to its superior electricalconductivity, film formability and film strength, while that having amass average molecular weight of 3,000 to 1,000,000 is more preferable,and that having a mass average molecular weight of 5,000 to 500,000 isthe most preferable.

Although the conducting polymer (a) can be used as is, the conductingpolymer (a) to which an external dopant has been imparted by dopingtreatment using acid according to known methods can also be used. Dopingtreatment can be carried out by, for example, immersing a conductorcontaining conducting polymer (a) in an acidic solution. Specificexamples of acidic solutions used in doping treatment include aqueoussolutions containing inorganic acids such as hydrochloric acid, sulfuricacid and nitric acid; organic acids such as p-toluene sulfonic acid,camphasulfonic acid, benzoic acid and derivatives having thesebackbones; and high molecular weight acids such as polystyrene sulfonicacid, polyvinyl sulfonic acid, poly(2-acrylamide-2-methylpropane)sulfonic acid, polyvinyl sulfuric acid and derivatives having thesebackbones; or mixed solutions of water and an organic solvent. Theseinorganic acids, organic acids and high molecular weight acids may eachbe used alone or they may be used as a mixture of two or more types atan arbitrary ratio.

<Heterocyclic Compound Trimer (i)>

An example of heterocyclic compound trimer (i) is the asymmetricalheterocyclic compound trimer represented by formula (16) in whichheterocyclic compounds are bonded asymmetrically:

(in the structural formula (16), wherein R¹⁰¹ to R¹¹² are substituentsrespectively and independently selected from the group consisting ofhydrogen, a linear or branched alkyl group having 1 to 24 carbon atoms,linear or branched alkoxy group having 1 to 24 carbon atoms, linear orbranched acyl group having 2 to 24 carbon atoms, aldehyde group,carboxyl group, linear or branched carboxylic ester group having 2 to 24carbon atoms, sulfonic acid group, linear or branched sulfonic estergroup having 1 to 24 carbon atoms, cyano group, hydroxyl group, nitrogroup, amino group, amido group, dicyanovinyl group, alkyl (linear orbranched alkyl group having 1 to 8 carbon atoms) oxycarbonylcyanovinylgroup, nitrophenylcyanovinyl group and halogen group;

Ht represents a heteroatom group selected from the group consisting ofNR¹⁵⁴, S, O, Se and Te, and R¹⁵⁴ represents a substituent selected fromthe group consisting of hydrogen and a linear or branched alkyl grouphaving 1 to 24 carbon atoms;

X^(a−) represents at least one type of anion selected from the groupconsisting of anions having a valence of 1 to 3 consisting of a chlorineion, bromine ion, iodine ion, fluorine ion, nitrate ion, sulfate ion,hydrogen sulfate ion, phosphate ion, borofluoride ion, perchlorate ion,thiocyanate ion, acetate ion, propionate ion, methane sulfonate ion,p-toluene sulfonate ion, trifluoroacetate ion and trifluoromethanesulfonate ion; a represents the ion valence of X and is an integer of 1to 3; and m represents the doping ratio and has a value of 0 to 3.0).

Heterocyclic compound trimer (i) is preferably a heterocyclic compoundtrimer represented by formula (17):

(in the structural formula (17), wherein R¹¹³ to R¹²⁴ representsubstituents respectively and independently selected from the groupconsisting of hydrogen, a linear or branched alkyl group having 1 to 24carbon atoms, linear or branched alkoxy group having 1 to 24 carbonatoms, linear or branched acyl group having 2 to 24 carbon atoms,aldehyde group, carboxyl group, linear or branched carboxylic estergroup having 2 to 24 carbon atoms, sulfonic acid group, linear orbranched sulfonic ester group having 1 to 24 carbon atoms, cyano group,hydroxyl group, nitro group, amino group, amido group, dicyanovinylgroup, alkyl (linear or branched alkyl group having 1 to 8 carbon atoms)oxycarbonylcyanovinyl group, nitrophenylcyanovinyl group and halogengroup; at least one of R¹¹³ to R¹²⁴ is a cyano group, nitro group, amidegroup, halogen group, sulfonic acid group, and carboxyl group;

Ht represents a heteroatom group selected from the group consisting ofNR¹⁵⁴, S, O, Se and Te, and R¹⁵⁴ represents a substituent selected fromthe group consisting of hydrogen and a linear or branched alkyl grouphaving 1 to 24 carbon atoms;

X^(a−) represents at least one type of anion selected from the groupconsisting of anions having a valence of 1 to 3 consisting of a chlorineion, bromine ion, iodine ion, fluorine ion, nitrate ion, sulfate ion,hydrogen sulfate ion, phosphate ion, borofluoride ion, perchlorate ion,thiocyanate ion, acetate ion, propionate ion, methanesulfonate ion,p-toluene sulfonate ion, trifluoroacetate ion and trifluoromethanesulfonate ion; a represents the ion valence of X and is an integer of 1to 3; and m represents the doping ratio and has a value of 0 to 3.0).

In addition, an example of an asymmetrical heterocyclic compound trimer(i) is the indole derivative trimer oxidant represented by generalformula (18):

(in the structural formula (18), wherein R¹²⁵ to R¹³⁶ are substituentsrespectively and independently selected from the group consisting ofhydrogen, a linear or branched alkyl group having 1 to 24 carbon atoms,linear or branched alkoxy group having 1 to 24 carbon atoms, linear orbranched acyl group having 2 to 24 carbon atoms, aldehyde group,carboxylic acid group and its alkaline metal salt, ammonium salt andsubstituted ammonium salt, linear or branched carboxylic ester grouphaving 2 to 24 carbon atoms, sulfonic acid group and its alkaline metalsalt, ammonium salt and substituted ammonium salt, linear or branchedsulfonic ester group having 1 to 24 carbon atoms, cyano group, hydroxylgroup, nitro group, amino group, amido group, dicyanovinyl group, alkyl(linear or branched alkyl group having 1 to 8 carbon atoms)oxycarbonylcyanovinyl group, nitrophenylcyanovinyl group and halogengroup;

X^(a−) represents at least one type of anion selected from the groupconsisting of anions having a valence of 1 to 3 consisting of a chlorineion, bromine ion, iodine ion, fluorine ion, nitrate ion, sulfate ion,hydrogensulfate ion, phosphate ion, borofluoride ion, perchlorate ion,thiocyanate ion, acetate ion, propionate ion, methanesulfonate ion,p-toluene sulfonate ion, trifluoroacetate ion and trifluoromethanesulfonate ion; a represents the ion valence of X and is an integer of 1to 3; and m represents the doping ratio and has a value of 0 to 3.0).

On the other hand, an example of heterocyclic compound trimer (i) usedin the present invention is a symmetrical heterocyclic compound trimerrepresented by general formula (19) in which heterocyclic compounds arebonded symmetrically:

(in the structural formula (19), wherein R¹³⁷ to R¹⁴⁸ are substituentsrespectively and independently selected from the group consisting ofhydrogen, a linear or branched alkyl group having 1 to 24 carbon atoms,linear or branched alkoxy group having 1 to 24 carbon atoms, linear orbranched acyl group having 2 to 24 carbon atoms, aldehyde group,carboxyl group, linear or branched carboxylic ester group having 2 to 24carbon atoms, sulfonic acid group, linear or branched sulfonic estergroup having 1 to 24 carbon atoms, cyano group, hydroxyl group, nitrogroup, amino group, amido group, dicyanovinyl group, alkyl (linear orbranched alkyl group having 1 to 8 carbon atoms) oxycarbonylcyanovinylgroup, nitrophenylcyanovinyl group and halogen group;

Ht represents a heteroatom group selected from the group consisting ofNR¹⁵⁴, S, O, Se and Te, and R¹⁵⁴ represents a substituent selected fromthe group consisting of hydrogen and a linear or branched alkyl grouphaving 1 to 24 carbon atoms;

X^(a−) represents at least one type of anion selected from the groupconsisting of anions having a valence of 1 to 3 consisting of a chlorineion, bromine ion, iodine ion, fluorine ion, nitrate ion, sulfate ion,hydrogensulfate ion, phosphate ion, borofluoride ion, perchlorate ion,thiocyanate ion, acetate ion, propionate ion, methanesulfonate ion,p-toluene sulfonate ion, trifluoroacetate ion and trifluoromethanesulfonate ion; a represents the ion valence of X and is an integer of 1to 3; and m represents the doping ratio and has a value of 0 to 3.0).

Among these heterocyclic compound trimers (i), carboxylgroup-substituted heterocyclic compound trimers, sulfonic acidgroup-substituted heterocyclic compound trimers, cyano group-substitutedheterocyclic compound trimers, nitro group-substituted heterocycliccompound trimers, amido group-substituted heterocyclic compound trimers,and halogen group-substituted heterocyclic compound trimers arepreferable in terms of practical use. In particular, trimers having anacidic group such as carboxyl group-substituted heterocyclic compoundtrimers, and sulfonic acid group-substituted heterocyclic compoundtrimers can be used preferably in terms of safety with respect to peopleand the environment since water can be used for the solvent due to theirwater solubility.

In addition, among these heterocyclic compound trimers (i), an indolederivative trimer in which the heterocyclic compound is an indolederivative (namely, a compound in which Ht is represented by NR¹⁵⁴) isused particularly preferably due to its high electrical conductivity andhigh solubility.

Heterocyclic compound trimers (i) obtained by various synthesis methodssuch as chemical synthesis and electrochemical synthesis can be used fora heterocyclic compound trimer (i) used in the present invention.

In the present invention, a heterocyclic compound trimer obtained byreacting at least one type of heterocyclic compound represented by thefollowing general formula (20) in a reaction mixture containing at leastone type of oxidizing agent and at least one type of solvent is usedparticularly preferably due to its high electrical conductivity and highsolubility.

(in the formula (20),wherein R¹⁵⁰ to R¹⁵³ are substituents respectivelyand independently selected from the group consisting of hydrogen, alinear or branched alkyl group having 1 to 24 carbon atoms, linear orbranched alkoxy group having 1 to 24 carbon atoms, linear or branchedacyl group having 2 to 24 carbon atoms, aldehyde group, carboxyl group,linear or branched carboxylic ester group having 2 to 24 carbon atoms,sulfonic acid group, linear or branched sulfonic ester group having 1 to24 carbon atoms, cyano group, hydroxyl group, nitro group, amino group,amido group, dicyanovinyl group, alkyl (linear or branched alkyl grouphaving 1 to 8 carbon atoms) oxycarbonylcyanovinyl group,nitrophenylcyanovinyl group and halogen group; and,

Ht represents a heteroatom group selected from the group consisting ofNR¹⁵⁴, S, O, Se and Te, and R¹⁵⁴ represents a substituent selected fromthe group consisting of hydrogen and a linear or branched alkyl grouphaving 1 to 24 carbon atoms).

Specific examples of the most typical indole derivatives represented bygeneral formula (20) used in the synthesis method of the heterocycliccompound trimer (i) include carboxyl group-substituted indoles, theiralkaline metal salts, ammonium salts and substituted ammonium salts suchas indole-4-carboxylic acid, indole-5-carboxylic acid,indole-6-carboxylic acid and indole-7-carboxylic acid; sulfonic acidgroup-substituted indoles, their alkaline metal salts, ammonium saltsand substituted ammonium salts such as indole-4-sulfonic acid,indole-5-sulfonic acid, indole-6-sulfonic acid and indole-7-sulfonicacid; alkyl group-substituted indoles such as 4-methylindole,5-methylindole, 6-methylindole, 7-methylindole, 4-ethylindole,5-ethylindole, 6-ethylindole, 7-ethylindole, 4-n-propylindole,5-n-propylindole, 6-n-propylindole, 7-n-propylindole,4-iso-propylindole, 5-iso-propylindole, 6-iso-propylindole,7-iso-propylindole, 4-n-butylindole, 5-n-butylindole, 6-n-butylindole,7-n-butylindole, 4-sec-butylindole, 5-sec-butylindole,6-sec-butylindole, 7-sec-butylindole, 4-t-butylindole, 5-t-butylindole,6-t-butylindole and 7-t-butylindole; alkoxy group-substituted indolessuch as 4-methoxyindole, 5-methoxyindole, 6-methoxyindole,7-methoxyindole, 4-ethoxyindole, 5-ethoxyindole, 6-ethoxyindole,7-ethoxyindole, 4-n-propoxyindole, 5-n-propoxyindole, 6-n-propoxyindole,7-n-propoxyindole, 4-iso-propoxyindole, 5-iso-propoxyindole,6-iso-propoxyindole, 7-iso-propoxyindole, 4-n-butoxyindole,5-n-butoxyindole, 6-n-butoxyindole, 7-n-butoxyindole,4-sec-butoxyindole, 5-sec-butoxyindole, 6-sec-butoxyindole,7-sec-butoxyindole, 4-t-butoxyindole, 5-t-butoxyindole, 6-t-butoxyindoleand 7-t-butoxyindole; acyl group-substituted indoles such as4-acetylindole, 5-acetylindole, 6-acetylindole and 7-acetylindole;aldehyde group-substituted indoles such as indole-4-carbaldehyde,indole-5-carbaldehyde, indole-6-carbaldehyde and indole-7-carbaldehyde;carboxylic ester group-substituted indoles such as methylindole-4-carboxylate, methyl indole-5-carboxylate, methylindole-6-carboxylate and methyl indole-7-carboxylate; sulfonic estergroup-substituted indoles such as methyl indole-4-sulfonate, methylindole-5-sulfonate, methyl indole-6-sulfonate and methylindole-7-sulfonate; cyano group-substituted indoles such asindole-4-carbonitrile, indole-5-carbonitrile, indole-6-carbonitrile andindole-7-carbonitrile; hydroxyl group-substituted indoles such as4-hydroxyindole, 5-hydroxyindole, 6-hydroxyindole and 7-hydroxyindole;nitro group-substituted indoles such as 4-nitroindole, 5-nitroindole,6-nitroindole and 7-nitroindole; amino group-substituted indoles such as4-aminoindole, 5-aminoindole, 6-aminoindole and 7-aminoindole; amidogroup-substituted indoles such as 4-carbamoylindole, 5-carbamoylindole,6-carbamoylindole and 7-carbamoylindole; halogen group-substitutedindoles such as 4-fluoroindole, 5-fluoroindole, 6-fluoroindole,7-fluoroindole, 4-chloroindole, 5-chloroindole, 6-chloroindole,7-chloroindole, 4-bromoindole, 5-bromoindole, 6-bromoindole,7-bromoindole, 4-iodoindole, 5-iodoindole, 6-iodoindole and7-iodoindole; dicyanovinyl group-substituted indoles such as4-dicyanovinylindole, 5-dicyanovinylindole, 6-dicyanovinylindole and7-dicyanovinylindole; and N-alkyl group-substituted indoles such asN-methylindole, N-ethylindole, N-n-propylindole, N-iso-propylindole,N-n-butylindole, N-sec-butylindole and N-t-butylindole.

Specific examples of the most typical benzo[b]furans represented bygeneral formula (20) include carboxyl group-substituted benzo[b]furans,their alkaline metal salts, ammonium salts and substituted ammoniumsalts such as benzo[b]furan-4-carboxylic acid,benzo[b]furan-5-carboxylic acid, benzo[b]furan-6-carboxylic acid andbenzo[b]furan-7-carboxylic acid; sulfonic acid group-substitutedbenzo[b]furans, their alkaline metal salts, ammonium salts andsubstituted ammonium salts such as benzo[b]furan-4-sulfonic acid,benzo[b]furan-5-sulfonic acid, benzo[b]furan-6-sulfonic acid andbenzo[b]furan-7-sulfonic acid; alkyl group-substituted benzo[b]furanssuch as 4-methylbenzo[b]furan, 5-methylbenzo[b]furan,6-methylbenzo[b]furan, 7-methylbenzo[b]furan, 4-ethylbenzo[b]furan,5-ethylbenzo[b]furan, 6-ethylbenzo[b]furan, 7-ethylbenzo[b]furan,4-n-propylbenzo[b]furan, 5-n-propylbenzo[b]furan,6-n-propylbenzo[b]furan, 7-n-propylbenzo[b]furan,4-iso-propylbenzo[b]furan, 5-iso-propylbenzo[b]furan,6-iso-propylbenzo[b] furan, 7-iso-propylbenzo[b]furan,4-n-butylbenzo[b]furan, 5-n-butylbenzo[b]furan, 6-n-butylbenzo[b]furan,7-n-butylbenzo[b]furan, 4-sec-butylbenzo[b]furan,5-sec-butylbenzo[b]furan, 6-sec-butylbenzo[b]furan,7-sec-butylbenzo[b]furan, 4-t-butylbenzo[b]furan,5-t-butylbenzo[b]furan, 6-t-butylbenzo[b]furan and7-t-butylbenzo[b]furan; alkoxy group-substituted benzo[b]furans such as4-methoxybenzo[b]furan, 5-methoxybenzo[b]furan, 6-methoxybenzo[b]furan,7-methoxybenzo[b]furan, 4-ethoxybenzo[b]furan, 5-ethoxybenzo[b]furan,6-ethoxybenzo[b]furan, 7-ethoxybenzo[b]furan, 4-n-propoxybenzo[b]furan,5-n-propoxybenzo[b]furan, 6-n-propoxybenzo[b]furan,7-n-propoxybenzo[b]furan, 4-iso-propoxybenzo[b]furan,5-iso-propoxybenzo[b]furan, 6-iso-propoxybenzo[b]furan,7-iso-propoxybenzo[b]furan, 4-n-butoxybenzo[b]furan,5-n-butoxybenzo[b]furan, 6-n-butoxybenzo[b]furan,7-n-butoxybenzo[b]furan, 4-sec-butoxybenzo[b]furan,5-sec-butoxybenzo[b]furan, 6-sec-butoxybenzo[b]furan,7-sec-butoxybenzo[b]furan, 4-t-butyoxybenzo[b]furan,5-t-butoxybenzo[b]furan, 6-t-butoxybenzo[b]furan and7-t-butoxybenzo[b]furan; acyl group-substituted benzo[b]furans such as4-acetylbenzo[b]furan, 5-acetylbenzo[b]furan, 6-acetylbenzo[b]furan and7-acetylbenzo[b]furan; aldehyde group-substituted benzo[b]furans such asbenzo[b]furan 4-carbaldehyde, benzo[b]furan 5-carbaldehyde,benzo[b]furan 6-carbaldehyde and benzo[b]furan 7-carbaldehyde;carboxylic ester-group substituted benzo[b]furans such as methylbenzo[b]furan-4-carboxylate, methyl benzo[b]furan-5-carboxylate, methylbenzo[b]furan-6-carboxylate and methyl benzo[b]furan-7-carboxylate;sulfonic ester-group substituted benzo[b]furans such as methylbenzo[b]furan-4-sulfonate, methyl benzo[b]furan-5-sulfonate, methylbenzo[b]furan-6-sulfonate and methyl benzo[b]furan-7-sulfonate; cyanogroup-substituted benzo[b]furans such as benzo[b]furan-4-carbonitrile,benzo[b]furan-5-carbonitrile, benzo[b]furan-6-carbonitrile andbenzo[b]furan-7-carbonitrile; hydroxyl group-substituted benzo[b]furanssuch as 4-hydroxybenzo[b]furan, 5-hydroxybenzo[b]furan,6-hydroxybenzo[b]furan and 7-hydroxybenzo[b]furan; nitrogroup-substituted benzo[b]furans such as 4-nitrobenzo[b]furan,5-nitrobenzo[b]furan, 6-nitrobenzo[b]furan and 7-nitrobenzo[b]furan;amino group-substituted benzo[b]furans such as 4-aminobenzo[b]furan,5-aminobenzo[b]furan, 6-aminobenzo[b]furan and 7-aminobenzo[b]furan;amido group-substituted benzo[b]furans such as 4-carbamoylbenzo[b]furan,5-carbamoylbenzo[b]furan, 6-carbamoylbenzo[b]furan and7-carbamoylbenzo[b]furan; halogen group-substituted benzo[b]furans suchas 4-fluorobenzo[b]furan, 5-fluorobenzo[b]furan, 6-fluorobenzo[b]furan,7-fluorobenzo[b]furan, 4-chlorobenzo[b]furan, 5-chlorobenzo[b]furan,6-chlorobenzo[b]furan, 7-chlorobenzo[b]furan, 4-bromobenzo[b]furan,5-bromobenzo[b]furan, 6-bromobenzo[b]furan, 7-bromobenzo[b]furan,4-iodobenzo[b]furan, 5-iodobenzo[b]furan, 6-iodobenzo[b]furan and7-iodobenzo[b]furan; dicyanovinyl group-substituted benzo[b]furans suchas 4-dicyanovinylbenzo[b]furan, 5-dicyanovinylbenzo[b]furan,6-dicyanovinylbenzo[b]furan and 7-dicyanovinylbenzo[b]furan; and N-alkylgroup-substituted benzo[b]furans such as N-methylbenzo[b]furan,N-ethylbenzo[b]furan, N-n-propylbenzo[b]furan,N-iso-propylbenzo[b]furan, N-n-butylbenzo[b]furan,N-sec-butylbenzo[b]furan and N-t-butylbenzo[b]furan.

Specific examples of the most typical benzo[b]thiophenes represented bygeneral formula (20) include carboxyl group-substitutedbenzo[b]thiophenes, their alkaline metal salts, ammonium salts andsubstituted ammonium salts such as benzo[b]thiophene-4-carboxylic acid,benzo[b]thiophene-5-carboxylic acid, benzo[b]thiophene-6-carboxylic acidand benzo[b]thiophene-7-carboxylic acid; sulfonic acid group-substitutedbenzo[b]thiophenes, their alkaline metal salts, ammonium salts andsubstituted ammonium salts such as benzo[b]thiophene-4-sulfonic acid,benzo[b]thiophene-5-sulfonic acid, benzo[b]thiophene-6-sulfonic acid andbenzo[b]thiophene-7-sulfonic acid; alkyl group-substitutedbenzo[b]thiophenes such as 4-methylbenzo[b]thiophene,5-methylbenzo[b]thiophene, 6-methylbenzo[b]thiophene,7-methylbenzo[b]thiophene, 4-ethylbenzo[b]thiophene,5-ethylbenzo[b]thiophene, 6-ethylbenzo[b]thiophene,7-ethylbenzo[b]thiophene, 4-n-propylbenzo[b]thiophene,5-n-propylbenzo[b]thiophene, 6-n-propylbenzo[b]thiophene,7-n-propylbenzo[b]thiophene, 4-iso-propylbenzo[b]thiophene,5-iso-propylbenzo[b]thiophene, 6-iso-propylbenzo[b]thiophene,7-iso-propylbenzo[b]thiophene, 4-n-butylbenzo[b]thiophene,5-n-butylbenzo[b]thiophene, 6-n-butylbenzo[b]thiophene,7-n-butylbenzo[b]thiophene, 4-sec-butylbenzo[b]thiophene,5-sec-butylbenzo[b]thiophene, 6-sec-butylbenzo[b]thiophene,7-sec-butylbenzo[b]thiophene, 4-t-butylbenzo[b]thiophene,5-t-butylbenzo[b]thiophene, 6-t-butylbenzo[b]thiophene and7-t-butylbenzo[b]thiophene; alkoxy group-substituted benzo[b]thiophenessuch as 4-methoxybenzo[b]thiophene, 5-methoxybenzo[b]thiophene,6-methoxybenzo[b]thiophene, 7-methoxybenzo[b]thiophene,4-ethoxybenzo[b]thiophene, 5-ethoxybenzo[b]thiophene,6-ethoxybenzo[b]thiophene, 7-ethoxybenzo[b]thiophene,4-n-propoxybenzo[b]thiophene, 5-n-propoxybenzo[b]thiophene,6-n-propoxybenzo[b]thiophene, 7-n-propoxybenzo[b]thiophene,4-iso-propoxybenzo[b]thiophene, 5-iso-propoxybenzo[b]thiophene,6-iso-propoxybenzo[b]thiophene, 7-iso-propoxybenzo[b]thiophene,4-n-butoxybenzo[b]thiophene, 5-n-butoxybenzo[b]thiophene,6-n-butoxybenzo[b]thiophene, 7-n-butoxybenzo[b]thiophene,4-sec-butoxybenzo[b]thiophene, 5-sec-butoxybenzo[b]thiophene,6-sec-butoxybenzo[b]thiophene, 7-sec-butoxybenzo[b]thiophene,4-t-butyoxybenzo[b]thiophene, 5-t-butoxybenzo[b]thiophene,6-t-butoxybenzo[b]thiophene and 7-t-butoxybenzo[b]thiophene; acylgroup-substituted benzo[b]thiophenes such as 4-acetylbenzo[b]thiophene,5-acetylbenzo[b]thiophene, 6-acetylbenzo[b]thiophene and7-acetylbenzo[b]thiophene; aldehyde group-substituted benzo[b]thiophenessuch as benzo[b]thiophene 4-carbaldehyde, benzo[b]thiophene5-carbaldehyde, benzo[b]thiophene 6-carbaldehyde and benzo[b]thiophene7-carbaldehyde; carboxylic ester-group substituted benzo[b]thiophenessuch as methyl benzo[b]thiophene-4-carboxylate, methylbenzo[b]thiophene-5-carboxylate, methyl benzo[b]thiophene-6-carboxylateand methyl benzo[b]thiophene-7-carboxylate; sulfonic ester-groupsubstituted benzo[b]thiophenes such as methylbenzo[b]thiophene-4-sulfonate, methyl benzo[b]thiophene-5-sulfonate,methyl benzo[b]thiophene-6-sulfonate and methylbenzo[b]thiophene-7-sulfonate; cyano group-substitutedbenzo[b]thiophenes such as benzo[b]thiophene-4-carbonitrile,benzo[b]thiophene-5-carbonitrile, benzo[b]thiophene-6-carbonitrile andbenzo[b]thiophene-7-carbonitrile; hydroxyl group-substitutedbenzo[b]thiophenes such as 4-hydroxybenzo[b]thiophene,5-hydroxybenzo[b]thiophene, 6-hydroxybenzo[b]thiophene and7-hydroxybenzo[b]thiophene; nitro group-substituted benzo[b]thiophenessuch as 4-nitrobenzo[b]thiophene, 5-nitrobenzo[b]thiophene,6-nitrobenzo[b]thiophene and 7-nitrobenzo[b]thiophene; aminogroup-substituted benzo[b]thiophenes such as 4-aminobenzo[b]thiophene,5-aminobenzo[b]thiophene, 6-aminobenzo[b]thiophene and7-aminobenzo[b]thiophene; amido group-substituted benzo[b]thiophenessuch as 4-carbamoylbenzo[b]thiophene, 5-carbamoylbenzo[b]thiophene,6-carbamoylbenzo[b]thiophene and 7-carbamoylbenzo[b]thiophene; halogengroup-substituted benzo[b]thiophenes such as 4-fluorobenzo[b]thiophene,5-fluorobenzo[b]thiophene, 6-fluorobenzo[b]thiophene,7-fluorobenzo[b]thiophene, 4-chlorobenzo[b]thiophene,5-chlorobenzo[b]thiophene, 6-chlorobenzo[b]thiophene,7-chlorobenzo[b]thiophene, 4-bromobenzo[b]thiophene,5-bromobenzo[b]thiophene, 6-bromobenzo[b]thiophene,7-bromobenzo[b]thiophene, 4-iodobenzo[b]thiophene,5-iodobenzo[b]thiophene, 6-iodobenzo[b]thiophene and7-iodobenzo[b]thiophene; dicyanovinyl group-substitutedbenzo[b]thiophenes such as 4-dicyanovinylbenzo[b]thiophene,5-dicyanovinylbenzo[b]thiophene, 6-dicyanovinylbenzo[b]thiophene and7-dicyanovinylbenzo[b]thiophene; and, N-alkyl group-substitutedbenzo[b]thiophenes such as N-methylbenzo[b]thiophene,N-ethylbenzo[b]thiophene, N-n-propylbenzo[b]thiophene,N-iso-propylbenzo[b]thiophene, N-n-butylbenzo[b]thiophene,N-sec-butylbenzo[b]thiophene and N-t-butylbenzo[b]thiophene.

Specific examples of the most typical benzo[b]selenophenes representedby general formula (20) include carboxyl group-substitutedbenzo[b]selenophenes, their alkaline metal salts, ammonium salts andsubstituted ammonium salts such as benzo[b]selenophene-4-carboxylicacid, benzo[b]selenophene-5-carboxylic acid,benzo[b]selenophene-6-carboxylic acid andbenzo[b]selenophene-7-carboxylic acid; sulfonic acid group-substitutedbenzo[b]selenophenes, their alkaline metal salts, ammonium salts andsubstituted ammonium salts such as benzo[b]selenophene-4-sulfonic acid,benzo[b]selenophene-5-sulfonic acid, benzo[b]selenophene-6-sulfonic acidand benzo[b]selenophene-7-sulfonic acid; alkyl group-substitutedbenzo[b]selenophenes such as 4-methylbenzo[b]selenophene,5-methylbenzo[b]selenophene, 6-methylbenzo[b]selenophene,7-methylbenzo[b]selenophene, 4-ethylbenzo[b]selenophene,5-ethylbenzo[b]selenophene, 6-ethylbenzo[b]selenophene,7-ethylbenzo[b]selenophene, 4-n-propylbenzo[b]selenophene,5-n-propylbenzo[b]selenophene, 6-n-propylbenzo[b]selenophene,7-n-propylbenzo[b]selenophene, 4-iso-propylbenzo[b]selenophene,5-iso-propylbenzo[b]selenophene, 6-iso-propylbenzo[b]selenophene,7-iso-propylbenzo[b]selenophene, 4-n-butylbenzo[b]selenophene,5-n-butylbenzo[b]selenophene, 6-n-butylbenzo[b]selenophene,7-n-butylbenzo[b]selenophene, 4-sec-butylbenzo[b]selenophene,5-sec-butylbenzo[b]selenophene, 6-sec-butylbenzo[b]selenophene,7-sec-butylbenzo[b]selenophene, 4-t-butylbenzo[b]selenophene,5-t-butylbenzo[b]selenophene, 6-t-butylbenzo[b]selenophene and7-t-butylbenzo[b]selenophene; alkoxy group-substitutedbenzo[b]selenophenes such as 4-methoxybenzo[b]selenophene,5-methoxybenzo[b]selenophene, 6-methoxybenzo[b]selenophene,7-methoxybenzo[b]selenophene, 4-ethoxybenzo[b]selenophene,5-ethoxybenzo[b]selenophene, 6-ethoxybenzo[b]selenophene,7-ethoxybenzo[b]selenophene, 4-n-propoxybenzo[b]selenophene,5-n-propoxybenzo[b]selenophene, 6-n-propoxybenzo[b]selenophene,7-n-propoxybenzo[b]selenophene, 4-iso-propoxybenzo[b]selenophene,5-iso-propoxybenzo[b]selenophene, 6-iso-propoxybenzo[b]selenophene,7-iso-propoxybenzo[b]selenophene, 4-n-butoxybenzo[b]selenophene,5-n-butoxybenzo[b]selenophene, 6-n-butoxybenzo[b]selenophene,7-n-butoxybenzo[b]selenophene, 4-sec-butoxybenzo[b]selenophene,5-sec-butoxybenzo[b]selenophene, 6-sec-butoxybenzo[b]selenophene,7-sec-butoxybenzo[b]selenophene, 4-t-butyoxybenzo[b]selenophene,5-t-butoxybenzo[b]selenophene, 6-t-butoxybenzo[b]selenophene and7-t-butoxybenzo[b]selenophene; acyl group-substitutedbenzo[b]selenophenes such as 4-acetylbenzo[b]selenophene,5-acetylbenzo[b]selenophene, 6-acetylbenzo[b]selenophene and7-acetylbenzo[b]selenophene; aldehyde group-substitutedbenzo[b]selenophenes such as benzo[b]selenophene 4-carbaldehyde,benzo[b]selenophene 5-carbaldehyde, benzo[b]selenophene 6-carbaldehydeand benzo[b]selenophene 7-carbaldehyde; carboxylic ester-groupsubstituted benzo[b]selenophenes such as methylbenzo[b]selenophene-4-carboxylate, methylbenzo[b]selenophene-5-carboxylate, methylbenzo[b]selenophene-6-carboxylate and methylbenzo[b]selenophene-7-carboxylate; sulfonic ester-group substitutedbenzo[b]selenophenes such as methyl benzo[b]selenophene-4-sulfonate,methyl benzo[b]selenophene-5-sulfonate, methylbenzo[b]selenophene-6-sulfonate and methylbenzo[b]selenophene-7-sulfonate; cyano group-substitutedbenzo[b]selenophenes such as benzo[b]selenophene-4-carbonitrile,benzo[b]selenophene-5-carbonitrile, benzo[b]selenophene-6-carbonitrileand benzo[b]selenophene-7-carbonitrile; hydroxyl group-substitutedbenzo[b]selenophenes such as 4-hydroxybenzo[b]selenophene,5-hydroxybenzo[b]selenophene, 6-hydroxybenzo[b]selenophene and7-hydroxybenzo[b]selenophene; nitro group-substitutedbenzo[b]selenophenes such as 4-nitrobenzo[b]selenophene,5-nitrobenzo[b]selenophene, 6-nitrobenzo[b]selenophene and7-nitrobenzo[b]selenophene; amino group-substituted benzo[b]selenophenessuch as 4-aminobenzo[b]selenophene, 5-aminobenzo[b]selenophene,6-aminobenzo[b]selenophene and 7-aminobenzo[b]selenophene; amidogroup-substituted benzo[b]selenophenes such as4-carbamoylbenzo[b]selenophene, 5-carbamoylbenzo[b]selenophene,6-carbamoylbenzo[b]selenophene and 7-carbamoylbenzo[b]selenophene;halogen group-substituted benzo[b]selenophenes such as4-fluorobenzo[b]selenophene, 5-fluorobenzo[b]selenophene,6-fluorobenzo[b]selenophene, 7-fluorobenzo[b]selenophene,4-chlorobenzo[b]selenophene, 5-chlorobenzo[b]selenophene,6-chlorobenzo[b]selenophene, 7-chlorobenzo[b]selenophene,4-bromobenzo[b]selenophene, 5-bromobenzo[b]selenophene,6-bromobenzo[b]selenophene, 7-bromobenzo[b]selenophene,4-iodobenzo[b]selenophene, 5-iodobenzo[b]selenophene,6-iodobenzo[b]selenophene and 7-iodobenzo[b]selenophene; dicyanovinylgroup-substituted benzo[b]selenophenes such as4-dicyanovinylbenzo[b]selenophene, 5-dicyanovinylbenzo[b]selenophene,6-dicyanovinylbenzo[b]selenophene and 7-dicyanovinylbenzo[b]selenophene;and, N-alkyl group-substituted benzo[b]selenophenes such asN-methylbenzo[b]selenophene, N-ethylbenzo[b]selenophene,N-n-propylbenzo[b]selenophene, N-iso-propylbenzo[b]selenophene,N-n-butylbenzo[b]selenophene, N-sec-butylbenzo[b]selenophene andN-t-butylbenzo[b]selenophene.

Specific examples of the most typical benzo[b]tellurophenes representedby general formula (20) include carboxyl group-substitutedbenzo[b]tellurophenes, their alkaline metal salts, ammonium salts andsubstituted ammonium salts such as benzo[b]tellurophene-4-carboxylicacid, benzo[b]tellurophene-5-carboxylic acid,benzo[b]tellurophene-6-carboxylic acid andbenzo[b]tellurophene-7-carboxylic acid; sulfonic acid group-substitutedbenzo[b]tellurophenes, their alkaline metal salts, ammonium salts andsubstituted ammonium salts such as benzo[b]tellurophene-4-sulfonic acid,benzo[b]tellurophene-5-sulfonic acid, benzo[b]tellurophene-6-sulfonicacid and benzo[b]tellurophene-7-sulfonic acid; alkyl group-substitutedbenzo[b]tellurophenes such as 4-methylbenzo[b]tellurophene,5-methylbenzo[b]tellurophene, 6-methylbenzo[b]tellurophene,7-methylbenzo[b]tellurophene, 4-ethylbenzo[b]tellurophene,5-ethylbenzo[b]tellurophene, 6-ethylbenzo[b]tellurophene,7-ethylbenzo[b]tellurophene, 4-n-propylbenzo[b]tellurophene,5-n-propylbenzo[b]tellurophene, 6-n-propylbenzo[b]tellurophene,7-n-propylbenzo[b]tellurophene, 4-iso-propylbenzo[b]tellurophene,5-iso-propylbenzo[b]tellurophene, 6-iso-propylbenzo[b]tellurophene,7-iso-propylbenzo[b]tellurophene, 4-n-butylbenzo[b]tellurophene,5-n-butylbenzo[b]tellurophene, 6-n-butylbenzo[b]tellurophene,7-n-butylbenzo[b]tellurophene, 4-sec-butylbenzo[b]tellurophene,5-sec-butylbenzo[b]tellurophene, 6-sec-butylbenzo[b]tellurophene,7-sec-butylbenzo[b]tellurophene, 4-t-butylbenzo[b]tellurophene,5-t-butylbenzo[b]tellurophene, 6-t-butylbenzo[b]tellurophene and7-t-butylbenzo[b]tellurophene; alkoxy group-substitutedbenzo[b]tellurophenes such as 4-methoxybenzo[b]tellurophene,5-methoxybenzo[b]tellurophene, 6-methoxybenzo[b]tellurophene,7-methoxybenzo[b]tellurophene, 4-ethoxybenzo[b]tellurophene,5-ethoxybenzo[b]tellurophene, 6-ethoxybenzo[b]tellurophene,7-ethoxybenzo[b]tellurophene, 4-n-propoxybenzo[b]tellurophene,5-n-propoxybenzo[b]tellurophene, 6-n-propoxybenzo[b]tellurophene,7-n-propoxybenzo[b]tellurophene, 4-iso-propoxybenzo[b]tellurophene,5-iso-propoxybenzo[b]tellurophene, 6-iso-propoxybenzo[b]tellurophene,7-iso-propoxybenzo[b]tellurophene, 4-n-butoxybenzo[b]tellurophene,5-n-butoxybenzo[b]tellurophene, 6-n-butoxybenzo[b]tellurophene,7-n-butoxybenzo[b]tellurophene, 4-sec-butoxybenzo[b]tellurophene,5-sec-butoxybenzo[b]tellurophene, 6-sec-butoxybenzo[b]tellurophene,7-sec-butoxybenzo[b]tellurophene, 4-t-butyoxybenzo[b]tellurophene,5-t-butoxybenzo[b]tellurophene, 6-t-butoxybenzo[b]tellurophene and7-t-butoxybenzo[b]tellurophene; acyl group-substitutedbenzo[b]tellurophenes such as 4-acetylbenzo[b]tellurophene,5-acetylbenzo[b]tellurophene, 6-acetylbenzo[b]tellurophene and7-acetylbenzo[b]tellurophene; aldehyde group-substitutedbenzo[b]tellurophenes such as benzo[b]tellurophene 4-carbaldehyde,benzo[b]tellurophene 5-carbaldehyde, benzo[b]tellurophene 6-carbaldehydeand benzo[b]tellurophene 7-carbaldehyde; carboxylic ester-groupsubstituted benzo[b]tellurophenes such as methylbenzo[b]tellurophene-4-carboxylate, methylbenzo[b]tellurophene-5-carboxylate, methylbenzo[b]tellurophene-6-carboxylate and methylbenzo[b]tellurophene-7-carboxylate; sulfonic ester-group substitutedbenzo[b]tellurophenes such as methyl benzo[b]tellurophene-4-sulfonate,methyl benzo[b]tellurophene-5-sulfonate, methylbenzo[b]tellurophene-6-sulfonate and methylbenzo[b]tellurophene-7-sulfonate; cyano group-substitutedbenzo[b]tellurophenes such as benzo[b]tellurophene-4-carbonitrile,benzo[b]tellurophene-5-carbonitrile, benzo[b]tellurophene-6-carbonitrileand benzo[b]tellurophene-7-carbonitrile; hydroxyl group-substitutedbenzo[b]tellurophenes such as 4-hydroxybenzo[b]tellurophene,5-hydroxybenzo[b]tellurophene, 6-hydroxybenzo[b]tellurophene and7-hydroxybenzo[b]tellurophene; nitro group-substitutedbenzo[b]tellurophenes such as 4-nitrobenzo[b]tellurophene,5-nitrobenzo[b]tellurophene, 6-nitrobenzo[b]tellurophene and7-nitrobenzo[b]tellurophene; amino group-substitutedbenzo[b]tellurophenes such as 4-aminobenzo[b]tellurophene,5-aminobenzo[b]tellurophene, 6-aminobenzo[b]tellurophene and7-aminobenzo[b]tellurophene; amido group-substitutedbenzo[b]tellurophenes such as 4-carbamoylbenzo[b]tellurophene,5-carbamoylbenzo[b]tellurophene, 6-carbamoylbenzo[b]tellurophene and7-carbamoylbenzo[b]tellurophene; halogen group-substitutedbenzo[b]tellurophenes such as 4-fluorobenzo[b]tellurophene,5-fluorobenzo[b]tellurophene, 6-fluorobenzo[b]tellurophene,7-fluorobenzo[b]tellurophene, 4-chlorobenzo[b]tellurophene,5-chlorobenzo[b]tellurophene, 6-chlorobenzo[b]tellurophene,7-chlorobenzo[b]tellurophene, 4-bromobenzo[b]tellurophene,5-bromobenzo[b]tellurophene, 6-bromobenzo[b]tellurophene,7-bromobenzo[b]tellurophene, 4-iodobenzo[b]tellurophene,5-iodobenzo[b]tellurophene, 6-iodobenzo[b]tellurophene and7-iodobenzo[b]tellurophene; dicyanovinyl group-substitutedbenzo[b]tellurophenes such as 4-dicyanovinylbenzo[b]tellurophene,5-dicyanovinylbenzo[b]tellurophene, 6-dicyanovinylbenzo[b]telluropheneand 7-dicyanovinylbenzo[b]tellurophene; and, N-alkyl group-substitutedbenzo[b]tellurophenes such as N-methylbenzo[b]tellurophene,N-ethylbenzo[b]tellurophene, N-n-propylbenzo[b]tellurophene,N-iso-propylbenzo[b]tellurophene, N-n-butylbenzo[b]tellurophene,N-sec-butylbenzo[b]tellurophene and N-t-butylbenzo[b]tellurophene.

Among these, carboxyl group-substituted heterocyclic compounds, sulfonicacid group-substituted heterocyclic compounds, cyano group-substitutedheterocyclic compounds, nitro group-substituted heterocyclic compounds,amido group-substituted heterocyclic compounds, halogengroup-substituted heterocyclic compounds and so forth are usedpreferably in terms of practical use. In particular, carboxylgroup-substituted heterocyclic compounds and sulfonic acidgroup-substituted heterocyclic compounds are used preferably.

Among these heterocyclic compounds, indole derivatives are usedpreferably.

There are no particular limitations on the oxidizing agent used in theaforementioned synthesis method of heterocyclic compound trimer (i), andexamples include ferric chloride hexahydrate, anhydrous ferric chloride,ferric nitrate nonahydrate, ferric sulfate n-hydrate, ammonium ferricsulfate dodecahydrate, ferric perchlorate n-hydrate, ferrictetrafluoroborate, cupric chloride, cupric nitrate, cupric sulfate,cupric tetrafluoroborate, nitrosonium tetrafluoroborate, hydrogenperoxide, ammonium persulfate, sodium persulfate, potassium persulfateand potassium periodate. Among these, ferric chloride hexahydrate,anhydrous ferric chloride, cupric chloride, cupric tetrafluoroborate andammonium persulfate are used preferably in terms of practical use, whileferric chloride hexahydrate and anhydrous ferric chloride are used mostpreferably in terms of practical use. Furthermore, these oxidizingagents may be used alone or two or more types may be combined at anarbitrary ratio.

The molar ratio of heterocyclic compound to oxidizing agent used in theaforementioned synthesis method of heterocyclic compound trimer (i)(heterocyclic compound: oxidizing agent) is 1:0.5 to 100, and preferably1:1 to 50. Here, if the ratio of the oxidizing agent is low, reactivitydecreases and raw materials remain. Conversely, if the ratio of theoxidizing agent is high, the trimer that is formed is oxidizedexcessively causing deterioration of the product.

Water or an inorganic solvent can be used for the solvent used in theaforementioned synthesis method of the heterocyclic compound trimer (i).There are no particular limitations on the organic solvent, and examplesof organic solvents that are used include methanol, ethanol,isopropanol, acetone, acetonitrile, propionitrile, tetrahydrofuran,1,4-dioxane, methyl isobutyl ketone, methyl ethyl ketone, y-butyllactone, propylene carbonate, sulfolane, nitromethane,N,N-dimethylformamide, N-methylacetoamide, dimethylsulfoxide,dimethylsulfone, N-methylpyrrolidone, benzene, toluene, xylene,methylene chloride, chloroform and dichloroethane. Furthermore, thesesolvents may be used alone or they may used as a mixture of two or moretypes at an arbitrary ratio. Among these solvents, acetone,acetonitrile, 1,4-dioxane, γ-butyl lactone and N,N-dimethylformamide areused preferably, while acetonitrile is used most preferably in terms ofpractical use.

In addition, in the aforementioned synthesis method of the heterocycliccompound trimer (i), the reaction is particularly preferably carried outin the presence of water and the organic solvent. The molar ratio of theheterocyclic compound to water (heterocyclic compound: water) is 1:1000to 1000:1 and preferably 1:100 to 100:1. However, in the case theoxidizing agent contains crystalline water, that crystalline water isalso calculated as water. Here, if the ratio of water is low, thereaction proceeds explosively, and simultaneous to excessive oxidationof the trimer and deterioration of its structure, X^(a−) serving asdopant may be unable to efficiently dope the trimer, thereby resultingin decreased electrical conductivity. Conversely, if the ratio of wateris excessively high, the progression of the oxidation reaction isobstructed which may cause a decrease in reaction yield.

In the aforementioned synthesis method of the heterocyclic compoundtrimer (i), the concentration of the heterocyclic compound during thereaction is 0.01% by mass or more, preferably 0.1 to 50% by mass, andmore preferably within the range of 1 to 30% by mass relative to thesolvent.

The X^(a−) in the heterocyclic compound trimers used in the presentinvention represented by general formulas (16) to (19) represents adopant, and is an anion of a protonic acid originating in the oxidizingagent and so forth during polymerization. More specifically, this anionis an anion having a valence of 1 to 3 such as chlorine ion, bromineion, iodine ion, fluorine ion, nitrate ion, sulfate ion, hydrogensulfate ion, phosphate ion, borofluoride ion, perchlorate ion,thiocyanate ion, acetate ion, propionate ion, p-toluene sulfonate ion,trifluoroacetate ion and trifluoromethane sulfonate ion, and ispreferably an anion having a valence of 1 to 2 such as a chlorine ion,sulfate ion or borofluoride ion. This anion is most preferably amonovalent anion such as chlorine ion. In the case of carrying outpolymerization by selecting anhydrous ferric chloride for the oxidizingagent, for example, dopant X^(a−) in the indole derivative trimer is achlorine ion, and in the case of carrying out polymerization usingcupric trifluoroacetate, dopant X^(a−) is a trifluoroacetate ion.

The heterocyclic compound trimer (i) obtained in the aforementionedsynthesis method of the heterocyclic compound trimer (i) is a dopedheterocyclic compound trimer (i) except for when hydrogen peroxide orozone is used for the oxidizing agent, and the molar ratio (dopingratio) of the dopant X^(a−) relative to its repeating unit is 0.001 to0.5. The value of m becomes 0 when hydrogen peroxide or ozone is usedfor the oxidizing agent.

A heterocyclic compound trimer that is dedoped for the purpose ofimproving solubility in solvent (b) can be used for the heterocycliccompound trimer (i). Although there are no particular limitations ondedoping method, methods known as dedoping steps of various types ofconducting polymers and charge transfer complexes in the prior art canbe used. Namely, examples of these methods include a method in whichindole derivative trimer (I) is suspended in an alkaline solution ofaqueous ammonia, sodium hydroxide, potassium hydroxide or lithiumhydroxide to remove dopant X^(a−), or a method in which a dedoped indolederivative trimer (namely, doping ratio m=0) is obtained by reductiontreatment.

The heterocyclic compound trimer (i) may have more superior electricalconductivity by having a layered structure. The heterocyclic compoundtrimer (i) preferably has a layered structure in which the interlayerinterval is 0.1 to 5.0 nm, more preferably 0.1 to 2.0 nm andparticularly preferably 0.1 to 1.0 nm. A compound having such amicrolayered structure has satisfactory rigidity, strength, heatresistance and so forth. If the interlayer interval is 0.1 nm or more,the layered structure tends to become more stable, and if the interlayerinterval is 2.0 nm or less, the hopping transfer of electrons betweentrimers becomes easier, thereby tending to improve electricalconductivity.

Furthermore, although the heterocyclic compound trimer (i) can be usedas is, that imparted with an external dopant can be used by carrying outdoping treatment by acid using a known method. For example, dopingtreatment can be carried out by immersing the heterocyclic compoundtrimer in an acidic solution. Specific examples of acidic solutions usedfor doping treatment include aqueous solutions containing inorganicacids such as hydrochloric acid, sulfuric acid and nitric acid, organicacids such as p-toluene sulfonic acid, camphasulfonic acid, benzoic acidand derivatives having these backbones, and high molecular weight acidssuch as polystyrene sulfonic acid, polyvinyl sulfonic acid,poly(2-acrylamide-2-methylpropane) sulfonic acid, polyvinyl sulfuricacid and derivatives having these backbones, or mixed solutions of waterand organic solvent. Furthermore, these inorganic acids, organic acidsand high molecular weight acids may each be used alone or they may beused as a mixture of two or more types at an arbitrary ratio.

In addition, although the indole derivative trimer oxidant representedby general formula (18), which is an asymmetrical heterocyclic compoundtrimer (i), can be obtained by a production method in which anasymmetrical indole derivative trimer is subjected to oxidationtreatment with a known oxidizing agent in a solvent, there are cases inwhich the indole derivative trimer oxidant can be obtained as a resultof the oxidation reaction proceeding more efficiently without using anoxidizing agent by simply dedoping an indole derivative trimer dopedwith an external dopant X^(a−) from the doped form by deacidificationtreatment or reduction treatment, thereby making this production methodextremely suitable industrially.

On the other hand, the heterocyclic compound oxidant represented bygeneral formula (19), which is the symmetrical heterocyclic compoundtrimer (i), can be obtained by a known production method. For example, asymmetrical indole derivative trimer can be produced according to themethod described in Japanese Unexamined Patent Application, FirstPublication No. 2001-261680.

The performance of these heterocyclic compound trimers (i) can beimproved by using after increasing their purity by using a purificationmethod such as recrystallization, reprecipitation purification orsublimation purification and so forth following their synthesis.

In the present invention, electrical conductivity, film formability andmoldability are improved as a result of containing this heterocycliccompound trimer.

<Solvent (b)>

There are no particular limitations on solvent (b), which is anessential component of the present invention, provided it dissolves ordisperses conducting polymer (a) or the heterocyclic compound trimer(i), carbon nanotubes (c), high molecular weight compound (d), basiccompound (e), surfactant (f), silane coupling agent (g) and colloidalsilica (h). Examples of the solvent (b) that are used preferably includewater, alcohols such as methanol, ethanol, isopropyl alcohol, propylalcohol and butanol; ketones such as acetone, methyl ethyl ketone, ethylisobutyl ketone and methyl isobutyl ketone; ethylene glycols such asethylene glycol, ethylene glycol methyl ether and ethylene glycolmono-n-propyl ether; propylene glycols such as propylene glycol,propylene glycol methyl ether, propylene glycol ethyl ether, propyleneglycol butyl ether and propylene glycol propyl ether; amides such asdimethylformamide and dimethylacetoamide; pyrrolidones such asN-methylpyrrolidone and N-ethylpyrrolidone; hydroxyesters such asdimethylsulfoxide, γ-butyrolactone, methyl lactate, ethyl lactate,methyl β-methoxyisobutyrate and methyl α-hydroxyisobutyrate; andanilines such as aniline and N-methylaniline.

In the case of using a water soluble conducting polymer for theconducting polymer (a), water or a water-containing organic solvent isused preferably for the solvent (b) in consideration of the solubilityof the water soluble conducting polymer and dispersivity of carbonnanotubes (c).

<Carbon Nanotubes (c)>

There are no particular limitations on carbon nanotubes (c), which arean essential component of the carbon nanotube composition of the presentinvention, and single-walled carbon nanotubes, multi-walled carbonnanotubes in which multiple walls are layered concentrically and theircoiled forms can be used for the carbon nanotubes (c).

As a more detailed explanation of the carbon nanotubes (c), an exampleof such a carbon nanotube is a substance in which the outer diameter isextremely small on the order of nanometers and which comprises aplurality of cylinders, in which the surfaces of graphite-like carbonatoms in layers several atoms thick are rounded, that form a nestedstructure. In addition, carbon nanohoms, in which one side of a carbonnanotube is closed, or cup-shaped nanocarbon substances, in which a holeis formed in the top, can also be used.

There are no particular limitations on the production method of thecarbon nanotubes (c) in the present invention. Specific examples ofproduction methods include catalytic hydrogen reduction of carbondioxide, arc discharge, laser vaporization, CVD, vapor phase growth andHiPco (high-pressure carbon monoxide process), in which carbon monoxideis reacted with an iron catalyst at high temperature and high pressureto grow carbon nanotubes in the vapor phase.

Preferable examples of carbon nanotubes (c) obtained by theaforementioned production methods are single-walled carbon nanotubes,and highly purified carbon nanotubes, which are obtained by variouspurification methods such as washing, centrifugal separation,filtration, oxidation and chromatography, are used preferably since theyadequately demonstrate various functions.

In addition, crushed carbon nanotubes obtained by crushing using a ballmill, vibration mill, sand mill, roll mill or other ball-type kneadingdevice, as well as shortly cut carbon nanotubes obtained by chemical orphysical treatment, can also be used.

<High Molecular Weight Compound (d)>

The use of high molecular weight compound (d) in the carbon nanotubecomposition of the present invention further improves the base materialadhesion and strength of the coated film.

There are no particular limitations on high molecular weight compound(d) in the present invention provided it can be dissolved or dispersed(emulsion formation) in the solvent (b) used in the present invention,specific examples of which include polyvinyl alcohols such as polyvinylalcohol, polyvinyl formal and polyvinyl butyral; polyacrylamides such aspolyacrylamide, poly(N-t-butylacrylamide and polyacrylamide methylpropane sulfonate; polyvinyl pyrrolidones; polystyrene sulfonates andtheir sodium salts; cellulose, alkyd resin, melamine resin, urea resin,phenol resin, epoxy resin, polybutadiene resin, acrylic resin, urethaneresin, vinyl ester resin, urea resin, polyimide resin, maleic acidresin, polycarbonate resin, vinyl acetate resin, chlorinatedpolyethylene resin, chlorinated polypropylene resin, styrene resin,acrylic/styrene copolymer resin, vinyl acetate/acrylic copolymer resin,polyester resin, styrene/maleic acid copolymer resin, fluororesin andtheir copolymers. In addition, these high molecular weight compounds (d)may be used as a mixture of two or more types at an arbitrary ratio.

Among these high molecular weight compounds (d), water soluble highmolecular weight compounds or high molecular weight compounds that forman emulsion in aqueous systems are used preferably in consideration ofsolubility in solvent, stability of the resulting composition andelectrical conductivity, and high molecular weight compounds having ananion group are used particularly preferably. In addition, among these,those used by mixing one or two or more types of aqueous acrylic resin,aqueous polyester resin, aqueous urethane resin and aqueous chlorinatedpolyolefin resin are used preferably.

<Basic Compound (e)>

The basic compound (e) that composes a carbon nanotube composition ofthe present invention is effective for dedoping the water solubleconducting polymer or the heterocyclic compound trimer and improvingsolubility in solvent (b) as a result of being added to the carbonnanotube composition. In addition, together with considerably improvingsolubility in water by forming salts with sulfonic acid groups andcarboxyl groups, basic compound (e) promotes solubilization ordispersion of the carbon nanotubes (c) in the solvent (b).

Although there are no particular limitations on the basic compound (e),examples of the basic compounds that are used preferably includeammonia, aliphatic amines, cyclic saturated amines, cyclic unsaturatedamines and ammonium salts, and inorganic bases.

The structural formula of amines used for the basic compound (e) isshown in the following formula (14):

(in the formula (14), wherein R⁴⁵ to R⁴⁷ respectively and mutuallyindependently represent hydrogen, alkyl group having 1 to 4 carbon atoms(C₁ to C₄), CH₂OH, CH₂CH₂OH, CONH₂ or NH₂).

The structural formula of ammonium salts used for basic compound (e) isshown in the following formula (15):

(in the formula (15), wherein R⁴⁸ to R⁵¹ respectively and mutuallyindependently represent hydrogen, alkyl group having 1 to 4 carbon atoms(C₁ to C₄), CH₂OH, CH₂CH₂OH, CONH₂ or NH₂, X⁻ represents OH⁻, ½.SO₄ ²⁻,NO₃ ⁻, ½.CO₃ ²⁻, HCO₃ ⁻, ½.(COO)₂ ²⁻ or R′COO⁻, and R′ represents analkyl group having 1 to 3 carbon atoms (C₁ to C₃)).

Examples of cyclic saturated amines that are used preferably includepiperidine, pyrrolidine, morpholine, piperazine, derivatives havingthese backbones and their ammonium hydroxide compounds.

Examples of cyclic unsaturated amines that are used preferably includepyridine, α-picoline, β-picoline, γ-picoline, quinoline, isoquinoline,pyrroline, derivatives having their backbones and their ammoniumhydroxide compounds.

Examples of inorganic bases that are used preferably include sodiumhydroxide, potassium hydroxide, lithium hydroxide and other hydroxides.

Two or more types of the basic compound (e) may be used by mixing. Forexample, electrical conductivity can be further improved by using amixture of an amine and an ammonium salt. Specific examples of suchmixtures include NH₃/(NH₄)₂CO₃, NH₃/(NH₄)HCO₃, NH₃/CH₃COONH₄,NH₃/(NH₄)₂SO₄, N(CH₃)₃/CH₃COONH₄ and N(CH₃)₃/(NH₄)₂SO₄. In addition,although these mixtures can be used in arbitrary mixing ratios, theratio of amine to ammonium salt (amine/ammonium salt) is preferably 1/10to 10/0.

<Surfactant (f)>

Although a carbon nanotube composition of the present invention is ableto form a high-performance film without undergoing separation ofaggregation even when stored for a long period of time by solubilizingor dispersing carbon nanotubes (c) with the aforementioned conductingpolymer (a) or heterocyclic compound trimer (i), solvent (b), carbonnanotubes (c), high molecular weight compound (d) and basic compound (e)alone, addition of surfactant (f) not only makes it possible to furtherpromote solubilization or dispersion, but also improves flatness,coatability and electrical conductivity.

Specific examples of the surfactant (f) that are used include anionicsurfactants such as alkyl sulfonic acid, alkyl benzene sulfonic acid,alkyl carboxylic acid, alkyl naphthalene sulfonic acid, α-olefinsulfonic acid, dialkyl sulfosuccinic acid, α-sulfonated fatty acids,N-methyl-N-oleyltaurine, petroleum sulfonic acid, alkyl sulfuric acids,sulfated oils, polyoxyethylene alkyl ether sulfuric acid,polyoxyethylene styrenated phenyl ether sulfuric acid, alkyl phosphoricacids, polyoxyethylene alkyl ether phosphoric acid, polyoxyethylenealkyl phenyl ether phosphoric acid, naphthalene sulfonic acidformaldehyde condensates and their salts; cationic surfactants such asprimary to tertiary fatty amines, quaternary ammonium, tetraalkylammonium, trialkyl benzyl ammonium alkyl pyridinium,2-alkyl-1-alkyl-1-hydroxyethyl imidazolinium, N,N-dialkylmorpholinium,polyethylene polyamine fatty acid amides, urea condensates ofpolyethylene polyamine fatty acid amides, quaternary ammonium of ureacondensates of polyethylene polyamine fatty acid amides and their salts;betaines such as N,N-dimethyl-N-alkyl-N-carboxymethyl ammonium betaines,N,N,N-trialkyl-N-sulfoalkylene ammonium betaines,N,N-dialkyl-N,N-bispolyoxyethylene ammonium sulfuric acid ester betainesand 2-alkyl-1-carboxymethyl-1-hydroxyethylimidazolinium betaines;amphoteric surfactants such as N,N-dialkylaminoalkylene carbonates;nonionic surfactants such as polyoxyethylene alkyl ethers,polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenylethers, polyoxyethylene-polyoxypropylene glycols,polyoxyethylene-polyoxypropylene alkyl ethers, polyvalent alcohol fattyacid partial esters, polyoxyethylene polyvalent alcohol fatty acidpartial esters, polyoxyethylene fatty acid esters, polyglycerin fattyacid esters, polyoxyethylenated castor oil, fatty acid diethanol amides,polyoxyethylene alkyl amines, triethanol amine fatty acid partial estersand trialkylamine oxides; and fluorine-based surfactants such asfluoroalkyl carboxylic acid, perfluoroalkyl carboxylic acid,perfluoroalkyl benzene sulfonic acid and perfluoroalkyl polyoxyethyleneethanol. Here, alkyl groups preferably have 1 to 24 carbon atoms andmore preferably 3 to 18 carbon atoms. Furthermore, two or more types ofsurfactants may be used.

<Silane Coupling Agent (g)>

A silane coupling agent (g) can be used in the present invention incombination with the carbon nanotube composition of the presentinvention containing the conducting polymer (a) or the heterocycliccompound trimer (i), the solvent (b), the carbon nanotubes (c), the highmolecular weight compound (d), the basic compound (e) and the surfactant(f). The moisture resistance of a coated film obtained from a carbonnanotube composition that uses a silane coupling agent (g) is remarkablyimproved. A silane coupling agent (g) represented by the followingformula (1) is used for silane coupling agent (g):

(in the formula (1) wherein, R²⁴², R²⁴³ and R²⁴⁴ respectively andindependently represent a group selected from the group consisting ofhydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms,linear or branched alkoxy group having 1 to 6 carbon atoms, amino group,acetyl group, phenyl group and halogen group, X represents thefollowing:

l and m represent values from 0 to 6, and Y represents a group selectedfrom the group consisting of a hydroxyl group, thiol group, amino group,epoxy group and epoxycyclohexyl group).

More specifically, examples of silane coupling agents having an epoxygroup include γ-glycidyloxypropyl trimethoxysilane, γ-glycidyloxypropylmethyl dimethoxysilane and γ-glycidyloxypropyl triethoxysilane.

Examples of silane coupling agents having an amino group includeγ-aminopropyl triethoxysilane, β-aminoethyl trimethoxysilane andγ-aminopropoxypropyl trimethoxysilane.

Examples of silane coupling agents having a thiol group includeγ-mercaptopropyl trimethoxysilane and β-mercaptoethyl methyldimethoxysilane.

Examples of silane coupling agents having a hydroxyl group includeβ-hydroxyethoxyethyl triethoxysilane and γ-hydroxypropyltrimethoxysilane.

Examples of silane coupling agents having an epoxycyclohexyl groupinclude β-(3,4-epoxycyclohexyl)ethyl trimethoxysilane.

<Colloidal Silica (h)>

In the present invention, colloidal silica (h) can also be used in acrosslinked carbon nanotube composition containing the conductingpolymer (a) or the heterocyclic compound trimer (i), the solvent (b),the carbon nanotubes (c), the high molecular weight compound (d), thebasic compound (e), the surfactant (f) and the silane coupling agent(g). A coated film obtained from a carbon nanotube composition thatcombines the use of colloidal silica (h) has remarkably improved surfacehardness and weather resistance.

Although there are no particular limitations on the colloidal silica (h)in the present invention, that which is dispersed in water, organicsolvent, or a mixed solvent of water and organic solvent is usedpreferably. Although there are no particular limitations on the organicsolvent, examples of organic solvents that are used preferably includealcohols such as methanol, ethanol, isopropyl alcohol, propyl alcohol,butanol and pentanol; ketones such as acetone, methyl ethyl ketone,ethyl isobutyl ketone and methyl isobutyl ketone; ethylene glycols suchas ethylene glycol, ethylene glycol methyl ether and ethylene glycolmono-n-propyl ether, and propylene glycols such as propylene glycol,propylene glycol methyl ether, propylene glycol ethyl ether, propyleneglycol butyl ether and propylene glycol propyl ether.

In addition, colloidal silica having a particle diameter within therange of 1 nm to 300 nm, preferably 1 nm to 150 nm and more preferably 1nm to 50 nm is used for the colloidal silica (h). Here, if the particlediameter is too large, hardness becomes inadequate or the solutionstability of the colloidal silica itself ends up decreasing.

<Carbon Nanotube Composition>

The usage ratio between the aforementioned conducting polymer (a) orheterocyclic compound trimer (i) and the solvent (b) is preferably 0.001to 50 parts by mass, and more preferably 0.01 to 30 parts by mass of theconducting polymer (a) or the heterocyclic compound trimer (i) relativeto 100 parts by mass of the solvent (b). If the ratio of the conductingpolymer (a) or the heterocyclic compound trimer (i) is less than 0.001parts by mass, electrical conductivity deteriorates or thesolubilization or dispersion efficiency of carbon nanotubes (c)decreases. On the other hand, if the ratio exceeds 50 parts by mass,electrical conductivity reaches a peak and does not increase further andviscosity becomes excessively high thereby causing a decrease in thesolubilization or dispersion efficiency of the carbon nanotubes (c).

The usage ratio between the aforementioned carbon nanotubes (c) andsolvent (b) is preferably 0.0001 to 20 parts by mass, and morepreferably 0.001 to 10 parts by mass of the carbon nanotubes (c)relative to 100 parts by mass of the solvent (b). If the ratio of thecarbon nanotubes (c) used is less than 0.0001 parts by mass, performancesuch as electrical conductivity resulting from the use of carbonnanotubes (c) decreases. On the other hand, if the amount used exceeds20 parts by mass, the solubilization or dispersion efficiency of thecarbon nanotubes (c) decreases.

The usage ratio between the aforementioned high molecular weightcompound (d) and solvent (b) is preferably 0.1 to 400 parts by mass, andmore preferably 0.5 to 300 parts by mass of the high molecular weightcompound (d) relative to 100 parts by mass of the solvent (b). If theratio of high molecular weight compound (d) is greater than or equal to0.1 parts by mass, film formablity, moldability and strength are furtherimproved, while on the other hand, when the ratio of the high molecularweight compound (d) is less than or equal to 400 parts by mass, there islittle decrease in the solubility of the water soluble conductingpolymer (a) or the heterocyclic compound trimer (i) or the carbonnanotubes (c), and a high degree of electrical conductivity ismaintained.

The usage ratio between the aforementioned basic compound (e) andsolvent (b) is preferably 0.1 to 10 parts by mass, and more preferably0.1 to 5 parts by mass of the basic compound (e) relative to 100 partsby mass of the solvent (b). When the usage ratio of the basic compound(e) is within this range, the solubility of the water soluble conductingpolymer improves, the solubilization or dispersion of the carbonnanotubes (c) in the solvent (b) is promoted, and electricalconductivity improves.

The usage ratio between the aforementioned surfactant (f) and solvent(b) is preferably 0.0001 to 10 parts by mass, and more preferably 0.01to 5 parts by mass of the surfactant (f) relative to 100 parts by massof the solvent (b). Although coatability improves if the usage ratio ofthe surfactant (f) exceeds 10 parts by mass, in addition to theoccurrence of phenomena such as deterioration of electricalconductivity, the solubilization or dispersion of the carbon nanotubes(c) decreases.

The usage ratio between the aforementioned silane coupling agent (g) andsolvent (b) is preferably 0.001 to 20 parts by mass, and more preferably0.01 to 15 parts by mass of the silane coupling agent (g) to 100 partsby mass of the solvent (b). If the usage ratio of the silane couplingagent (g) is less than 0.001 parts by mass, the amount of improvement inat least one of moisture resistance and solvent resistance becomescomparatively smaller, while on the other hand, if the usage ratioexceeds 20 parts by mass, solubility, flatness, transparency andelectrical conductivity may worsen.

The usage ratio between the aforementioned colloidal silica (h) andsolvent (b) is preferably 0.001 to 100 parts by mass, and morepreferably 0.01 to 50 parts by mass of the colloidal silica (h) relativeto 100 parts by mass of the solvent (b). If the ratio of the colloidalsilica (h) is 0.001 parts by mass or more, the amount of improvement inmoisture resistance, weather resistance and hardness increases. On theother hand, if the ratio exceeds 100 parts by mass, solubility,flatness, transparency and electrical ductivity worsen.

Moreover, various types of known substances can be added to the carbonnanotube composition of the present invention as necessary, examples ofwhich include plasticizers, dispersants, coated surface adjusters,fluidity adjusters, ultraviolet absorbers, antioxidants, preservatives,adhesion assistants and thickeners.

In addition, an conducting substance can be incorporated in the carbonnanotube composition of the present invention in order to furtherimprove electrical conductivity. Examples of the conducting substancesinclude carbon fibers, conducting carbon black, graphite and othercarbon-based substances, tin oxide, zinc oxide and other metal oxides,and metals such as silver, nickel and copper.

<Production Method of Carbon Nanotube Composition>

A stirring or kneading device such as an ultrasonic wave device,homogenizer, spiral mixer, planetary mixer, dispenser or hybrid mixer isused when mixing these components. In particular, it is preferable tomix the conducting polymer (a) or the heterocyclic compound trimer (i),the solvent (b), the carbon nanotubes (c) and other components andirradiate them with ultrasonic waves,. At that time, it is preferable touse irradiation of ultrasonic waves in combination with a homogenizer(ultrasonic homogenizer).

Although there are no particular limitations on the conditions ofirradiation with ultrasonic waves, the intensity and treatment time ofthe ultrasonic waves should be adequate for uniformly dispersing ordissolving the carbon nanotubes (c) in the solvent (b). For example, therated output of an ultrasonic oscillator is preferably within the rangeof 0.1 to 2.0 watts/cm², and more preferably 0.3 to 1.5 watts/cm², perunit bottom surface area of the ultrasonic oscillator, and theoscillation frequency is preferably within the range of 10 to 200 KHzand more preferably 20 to 100 KHz. In addition, the duration ofultrasonic irradiation treatment is preferably 1 minute to 48 hours andmore preferably 5 minutes to 48 hours. Dispersion or dissolution ispreferably subsequently improved by using a ball-type kneading devicesuch as a ball mill, vibration mill, sand mill or roll mill.

<Composite>

Examples of base materials that form a coated film by coating with thecarbon nanotube composition in the present invention include highmolecular weight compounds, plastics, wood, paper, ceramics, fibers,non-woven fabrics, carbon fibers, carbon fiber paper and their films,foams, porous films, elastomers and glass plates.

Examples of high molecular weight compounds, plastics and films includepolyethylene, polyvinyl chloride, polypropylene, polystyrene, ABS resin,AS resin, methacrylic resin, polybutadiene, polycarbonate, polyarylate,polyvinylidene fluoride, polyester, polyamide, polyimide, polyaramid,polyphenylene sulfide, polyether ethyl ketone, polyphenylene ether,polyether nitrile, polyamide imide, polyether sulfone, polysalfone,polyether imide, polybutylene terephthalate, polyurethane and theirfilms, foams and elastomers. In order to form a coated film on at leastone of their surfaces, the surfaces of these films are preferablysubjected to corona discharge treatment or plasma treatment for thepurpose of improving adhesion of the coated film.

A coated film in the present invention is formed on the surface of abase material by a method used for ordinary coating. Examples of methodsused include coating methods using a gravure coater, roll coater,curtain flow coater, spin coater, bar coater, reverse coater, kisscoater, fountain coater, rod coater, air doctor coater, knife coater,blade coater, cast coater or screen coater, spraying methods such as airspraying or airless spraying, and immersion methods such as dipping.

Although the carbon nanotube composition can be allowed to stand atnormal temperatures after coating onto the surface of a base material,the coated film can also be heat-treated. The performing of heattreatment is preferable since the crosslinking reaction between thecarbon nanotubes (c), the high molecular weight compound (d) and thebasic compound (e) and the conducting polymer (a) or the heterocycliccompound trimer (i) can be further promoted, moisture resistance can beimparted in a shorter period of time, the residual amount of the solvent(b) can be further reduced and electrical conductivity can be furtherimproved. The temperature of heat treatment is preferably 20 to 250° C.and particularly preferably 40 to 200° C. If the temperature of heattreatment is higher than 250° C., the conducting polymer (a) itself orthe heterocyclic compound trimer (i) itself is decomposed, andelectrical conductivity may be degraded.

The film thickness of the coated film is preferably within the range of0.01 to 100 μm, and more preferably within the range of 0.1 to 50 μm.

Although the composite of the present invention has superior electricalconductivity even if used as is, electrical conductivity can be furtherimproved by doping with acid after having formed a coated film of thecarbon nanotube composition on at least one surface of the basematerial, and then allowing to stand at ordinary temperatures or heattreating.

There are no particular limitations on the method used for acid dopingand known methods can be used. For example, doping can be carried out byimmersing a conductor in an acidic solution. Specific examples of acidicsolutions include aqueous solutions containing inorganic acids such ashydrochloric acid, sulfuric acid and nitric acid, organic acids such asp-toluene sulfonic acid, camphasulfonic acid, benzoic acid, andderivatives having their backbones, and high molecular weight acids suchas polystyrene sulfonic acid, polyvinyl sulfonic acid,poly(2-acrylamide-2-methylpropane) sulfonic acid, polyvinyl sulfuricacid and derivatives having their backbones, as well as mixed solventsof water and organic solvent. Furthermore, these inorganic acids,organic acids and high molecular weight acids may each be used alone ortwo or more types may be used as a mixture at an arbitrary ratio.

Although the following provides a more detailed explanation of thepresent invention through its examples, the following examples are notintended to limit the scope of the present invention in any way.

<Production of Conducting Polymer>

PRODUCTION EXAMPLE 1 Conducting Polymer (A-1) Synthesis ofPoly(2-sulfo-5-methoxy-1,4-iminophenylene)

100 mmol of 2-aminoanisol-4-benzene sulfonic acid were stirred anddissolved in a 4 mol/liter aqueous solution of triethylamine at 25° C.,then a 100 mmol aqueous solution of ammonium peroxodisulfate was droppedin the mixture. Following completion of dropping and stirring for anadditional 12 hours at 25° C., the reaction product was filtered, washedand then dried to obtain 15 g of a polymer powder. The volumetricresistance of this conducting polymer (A-1) was 9.0 Ω·cm.

PRODUCTION EXAMPLE 2 Conducting Polymer (A-2) Synthesis ofPoly(2-sulfo-1,4-iminophenylene)

100 mmol of m-aminobenzene sulfonic acid were stirred and dissolved in a4 mol/liter aqueous solution of trimethylamine at 25° C., then a 100mmol aqueous solution of ammonium peroxodisulfate was dropped in themixture. Following completion of dropping and stirring for an additional12 hours at 25° C., the reaction product was filtered, washed and thendried to obtain 10 g of a polymer powder. The volumetric resistance ofthis conducting polymer (A-2) was 12.0 Ω·cm.

PRODUCTION EXAMPLE 3 Conducting Polymer (A-3) Synthesis of SulfonatedPolyaniline

Poly(2-sulfo-1,4-iminophenylene) was synthesized according to a knownmethod (J. Am. Chem. Soc., (1991), 113, 2665-2666). The sulfonic acidcontent of the resulting polymer was 52% relative to the aromatic ring.In addition, the volumetric resistance of this conducting polymer (A-3)was 50 Ω·cm.

PRODUCTION EXAMPLE 4 Conducting Polymer (A-4) Synthesis of DedopedPolyaniline

100 mmol of aniline were stirred and dissolved in a 1 mol/liter aqueoussolution of sulfuric acid at 25° C., followed by dropping in a 100 mmolaqueous solution of ammonium peroxodisulfate. Following completion ofdropping and stirring for an additional 12 hours at 25° C., the reactionproduct was filtered, washed and then dried to obtain 8 g of a polymerpowder. The resulting doped polymer was press molded with a tabletmolding machine and cut to a diameter of 10 mm and thickness of 1 mm.When the conductivity was measured with the four probe method, it wasfound to be 1.0 S/cm or less. After dispersing and stirring this polymerin 1 mol/liter aqueous ammonia for 1 hour at 25° C., it was filtered,washed and then dried to obtain 5 g of dedoped polymer powder.

<Preparation of Carbon Nanotube Composition>

EXAMPLE 1

5 parts by mass of the aforementioned conducting polymer (A-1) ofProduction Example 1 and 0.4 parts by mass of carbon nanotubes (Iljin,multi-walled carbon nanotubes produced by CVD) were mixed in 100 partsby mass of water at room temperature to prepare a carbon nanotubecomposition 1.

EXAMPLE 2

5 parts by mass of the aforementioned conducting polymer (A-1) ofProduction Example 1, 0.1 parts by mass of carbon nanotubes and 20 partsby mass of acrylic resin in an aqueous emulsion form (Dianal MX-1845,Mitsubishi Rayon Co., Ltd., resin content: 40% by mass) were mixed in100 parts of water at room temperature to prepare a carbon nanotubecomposition 2.

EXAMPLE 3

3 parts by mass of the aforementioned conducting polymer (A-2) ofProduction Example 2, 0.1 parts by mass of carbon nanotubes and 1 partby mass of ammonia were mixed in 100 parts by mass of water at roomtemperature to prepare a carbon nanotube composition 3.

EXAMPLE 4

1 part by mass of the aforementioned conducting polymer (A-1) ofProduction Example 1, 0.2 parts by mass of carbon nanotubes, 1 part bymass of triethylamine and 20 parts by mass of acrylic resin in anaqueous emulsion form (Dianal MX-1845, Mitsubishi Rayon Co., Ltd.) weremixed in 100 parts by mass of water at room temperature to a preparecarbon nanotube composition 4.

EXAMPLE 5

1 part by mass of the aforementioned conducting polymer (A-3) ofProduction Example 3, 0.4 parts by mass of carbon nanotubes and 0.5parts by mass of dodecylbenzene sulfonate were mixed in 100 parts bymass of a water/methanol mixed solvent (weight ratio: 9/1) at roomtemperature to prepare a carbon nanotube composition 5.

EXAMPLE 6

1 part by mass of the aforementioned conducting polymer (A-1) ofProduction Example 1, 0.4 parts by mass of carbon nanotubes and 0.5parts by mass of γ-glycidoxypropyl trimethoxysilane were mixed in 100parts by mass of water at room temperature to prepare a carbon nanotubecomposition 6.

EXAMPLE 7

1 part by mass of the aforementioned conducting polymer (A-1) ofProduction Example 1, 0.4 parts by mass of carbon nanotubes, 0.5 partsby mass of γ-glycidoxypropyl trimethoxysilane, 5 parts by mass ofcolloidal silica (particle diameter: 10 nm) and 10 parts by mass ofacrylic resin in an aqueous emulsion form (Dianal MX-1845, MitsubishiRayon Co., Ltd.) were mixed in 100 parts of water at room temperature toprepare a carbon nanotube composition 7.

EXAMPLE 8

0.5 parts by mass of the aforementioned conducting polymer (A-4) ofProduction Example 4 and 0.1 parts by mass of carbon nanotubes weremixed in 100 parts by mass of N-methylpyrrolidone at room temperature toprepare a carbon nanotube composition 8.

COMPARATIVE EXAMPLE 1

0.1 part by mass of carbon nanotubes were mixed in 100 parts by mass ofwater at room temperature to prepare a carbon nanotube composition 8.

COMPARATIVE EXAMPLE 2

0.1 part by mass of carbon nanotubes and 1 part by mass of ammonia weremixed in 100 parts by mass of water at room temperature to prepare acarbon nanotube composition 9.

COMPARATIVE EXAMPLE 3

0.1 part by mass of carbon nanotubes and 20 parts by mass of acrylicresin in an aqueous emulsion form (Dianal Mx-1845, Mitsubishi Rayon Co.,Ltd.) were mixed in 100 parts by mass of water at room temperature toprepare a carbon nanotube composition 10.

COMPARATIVE EXAMPLE 4

5 parts by mass of the aforementioned conducting polymer (A-1) ofProduction Example 1 were mixed in 100 parts by mass of water at roomtemperature to prepare a conducting composition 1.

In the following production examples of indole derivative trimers,elementary analysis and measurements were carried out using theThermoquest EA1110. Electrical conductivity was measured with theMCP-T350 conductivity gauge (Mitsubishi Chemical) (four probe method,electrode interval: 1 mm). Moreover, X-ray diffraction (XRD) wasmeasured with the RINT-1100 (Rigaku Corporation) (tube: CuK, X-rays).

PRODUCTION EXAMPLE 5 Synthesis of Indole-5-Carboxylic Acid Trimer

10 ml of acetonitrile were placed in a 200 ml three-mouth flask followedby dissolving 1.42 g of indole-5-carboxylic acid. On the other hand,preparation of the oxidizing agent solution was carried out bydissolving 16.2 g of anhydrous ferric chloride and 5.4 g of water in 40ml of acetonitrile and stirring for 10 minutes. Next, after dropping inthe prepared oxidizing agent solution into the aqueousindole-5-carboxylic acid solution over the course of 30 minutes, thesolution was stirred for 10 hours at 60° C. The reaction solutionchanged from a pale yellow color to a light green color while generatinga small amount of heat, and its pH was 1 or less. Following completionof the reaction, the reaction solution was aspiration filtered with aKiriyama funnel, washed with acetonitrile and then methanol and dried toobtain 1.12 g of light green6,11-dihydro-5H-diindolo[2,3-a:2′,3′-c]carbazole-2,9,14-tricarboxylicacid (indole-5-carboxylic acid trimer) (yield: 79%).

When the resulting trimer was press molded with a tablet molding machineand cut to a diameter of 10 mm and thickness of 1 mm followed bymeasurement of electrical conductivity using the four probe method, itwas 0.41 S/cm. The result of elementary analysis was(C_(9.00)H_(4.90)N_(1.09)O_(1.98)Cl_(0.11))₃. In addition, the result ofX-ray diffraction crystal analysis was an interlayer interval of 0.48nm.

PRODUCTION EXAMPLE 6 Synthesis of Indole-5-Sulfonic Acid Trimer

With the exception of using indole-5-sulfonic acid instead ofindole-5-carboxylic acid in Production Example 5, polymerization wascarried out in the same manner as Production Example 5 to obtain 1.01 gof green6,11-dihydro-5H-diindolo[2,3-a:2′,3′-c]carbazole-2,9,14-trisulfonic acid(indole-5-sulfonic acid trimer) (yield: 71%).

When the resulting trimer was press molded with a tablet molding machineand cut to a diameter of 10 mm and thickness of 1 mm followed bymeasurement of electrical conductivity using the four probe method, itwas 0.56 S/cm. The result of elementary analysis was(C_(8.00)H_(4.85)N_(1.06)O_(3.01)S_(1.06)Cl_(0.11))₃.

PRODUCTION EXAMPLE 7 Synthesis of Indole-5-Carbonitrile Trimer

With the exception of using indole-5-carbonitrile instead ofindole-5-carboxylic acid in Production Example 5, polymerization wascarried out in the same manner as Production Example 5 to obtain 1.22 gof green6,11-dihydro-5H-diindolo[2,3-a:2′,3′-c]carbazole-2,9,14-tricarbonitrile(indole-5-carbonitrile trimer) (yield: 86%).

When the resulting trimer was press molded with a tablet molding machineand cut to a diameter of 10 mm and thickness of 1 mm followed bymeasurement of electrical conductivity using the four probe method, itwas 0.50 S/cm. The result of elementary analysis was(C_(9.00)H_(4.03)N_(1.97)Cl_(0.10))₃. In addition, the result of X-raydiffraction cry analysis was an interlayer interval of 0.44 nm.

PRODUCTION EXAMPLE 8 Synthesis of Indole-5-Carboxylic Acid TrimerOxidant

1.00 g of the indole-5-carboxylic acid trimer synthesized in ProductionExample 5 was dissolved in 50 ml of 1 M aqueous ammonia and stirred for1 hour. After stirring, it was re-precipitated in 50 ml of acetonitrileand the resulting precipitate was suction filtered with a Kiriyamafunnel, washed with water and then acetonitrile and dried to obtain 0.92g of the black oxidant of indole-5-carboxylic acid trimer. The result ofelementary analysis was (C_(9.00)H_(4.34)N_(1.07)O_(1.99))₃.

PRODUCTION EXAMPLE 9 Synthesis of Symmetrical Indole Trimer

50.0 g of oxyindole were stirred for 10 hours at 100° C. in air using100 ml of phosphorous oxychloride as solvent in a 300 ml three-mouthflask. After slowly pouring the reaction liquid into ice water andcrushing the excess phosphorous oxychloride, the liquid was neutralizedwith aqueous sodium hydroxide. The target compound was then extractedfrom this solution with chloroform and dried with magnesium sulfate. Thesolvent was distilled off from the filtrate and purified by columnchromatography to obtain 32.5 g of indole trimer (symmetrical form).

EXAMPLE 9

5 parts by mass of the aforementioned indole-5-carboxylic acid trimer ofProduction Example 5 and 0.4 parts by mass of carbon nanotubes (Iljin,multi-walled carbon nanotubes produced by CVD) were mixed in 100 partsby mass of water at room temperature to prepare a carbon nanotubecomposition.

EXAMPLE 10

3 parts by mass of the aforementioned indole-5-carboxylic acid trimer ofProduction Example 5, 0.1 parts by mass of carbon nanotubes and 20 partsby mass of acrylic resin in an aqueous emulsion form (Dianal MX-1845,Mitsubishi Rayon Co., Ltd.) were mixed in 100 parts by mass of water atroom temperature to prepare a carbon nanotube composition.

EXAMPLE 11

3 parts by mass of the aforementioned indole-5-sulfonic acid trimer ofProduction Example 6, 0.1 parts by mass of carbon nanotubes and 1 partby mass of ammonia were mixed in 100 parts by mass of water at roomtemperature to prepare a carbon nanotube composition.

EXAMPLE 12

3 parts by mass of the aforementioned indole-5-sulfonic acid trimer ofProduction Example 6, 0.2 parts by mass of carbon nanotubes, 1 part bymass of triethylamine and 20 parts by mass of acrylic resin in anaqueous emulsion form (Dianal MX-1845, Mitsubishi Rayon Co., Ltd.) weremixed in 100 parts by mass of water at room temperature to prepare acarbon nanotube composition.

EXAMPLE 13

1 part by mass of the aforementioned indole-5-carbonitrile trimer ofProduction Example 7, 0.4 parts by mass of carbon nanotubes and 0.5parts by mass of dodecylbenzene sulfonate were mixed in 100 parts bymass of dimethylsulfoxide at room temperature to prepare a carbonnanotube composition.

EXAMPLE 14

3 parts by mass of the aforementioned indole-5-carboxylic acid trimeroxidant of Production Example 8, 0.4 parts by mass of carbon nanotubesand 0.5 parts by mass of γ-glycidoxypropyl trimethoxysilane were mixedin 100 parts by mass of water at room temperature to prepare a carbonnanotube composition.

EXAMPLE 15

3 parts by mass of the aforementioned symmetrical indole trimer ofProduction Example 9, 0.4 parts by mass of carbon nanotubes and 10 partsby mass of acrylic resin in an aqueous emulsion form (Dianal MX-1845,Mitsubishi Rayon Co., Ltd.) were mixed in 100 parts by mass of water atroom temperature to prepare a carbon nanotube composition.

COMPARATIVE EXAMPLE 5

1 part by mass of the aforementioned indole-5-carbonitrile trimer ofProduction Example 7 and 0.5 parts by mass of dodecylbenzene sulfonatewere mixed in 100 parts by mass of dimethylsulfoxide at room temperatureto prepare a conducting composition.

<Evaluation Method>

Absence of Ultrasonic Treatment

After visually observing the states of the compositions obtained in theaforementioned examples and comparative examples, the compositions werecoated onto a glass plate according to the bar coater method (using aNo. 5 bar coater). After drying for 5 minutes at 80° C. to form a coatedfilm and then observing its appearance, the surface resistance wasmeasured. Those results are shown in Table 1.

However, in the case of carbon nanotube composition 8 obtained inExample 8, the composition was coated onto a glass plate according tothe bar coater method (using a No. 5 bar coater) and dried for 5 minutesat 1 50° C. to form a coated film followed by immersing for 5 minutes ina 1 mol/liter aqueous solution of sulfuric acid. After then drying for 5minutes at 80° C. and observing the appearance, the surface resistancewas measured.

Presence of Ultrasonic Treatment

The compositions obtained in the aforementioned examples and comparativeexamples were subjected to ultrasonic treatment for 1 hour (UA100,Shinmei Daiko, 36 KHz), and after visually observing the states of thecompositions, the compositions were coated onto a glass plate accordingto the bar coater method (using a No. 5 bar coater). After drying for 5minutes at 80° C. to form a coated film and then observing itsappearance, the surface resistance was measured. Those results are shownin Table 1.

However, in the case of carbon nanotube composition 8 obtained inExample 8, the composition was coated onto a glass plate according tothe bar coater method (using a No. 5 bar coater) and dried for 5 minutesat 150° C. to form a coated film followed by immersing for 5 minutes ina 1 mol/liter aqueous solution of sulfuric acid. After then drying for 5minutes at 80° C. and observing the appearance, the surface resistancewas measured.

Solution State

The solution state was observed visually 24 hours after having preparedthe carbon nanotube compositions. Those results are shown in Table 1.

∘: Uniformly dispersed or dissolved

X: Non-uniformly dispersed

Surface Resistance

The two probe method (electrode interval: 20 mm) was used to measuresurface resistance under conditions of 25° C. and 15% RH for surfaceresistance values of 10⁸ Ω or more, while the four probe method(electrode interval: 5 mm) was used for surface resistance values of 10⁷Ω or less. Those results are shown in Table 1.

Coated Film Appearance

The state of the coated film was observed visually. Those results areshown in Table 1.

∘: Uniform coated film formed

X: Coated film observed in which carbon nanotubes are not presentuniformly

TABLE 1 Ultrasonic Surface Coated Film Treatment Solution StateResistance Appearance Example 1 No ◯ 6.6 × 10³ ◯ Yes ◯ 1.9 × 10² ◯Example 2 No ◯ 8.3 × 10⁴ ◯ Yes ◯ 6.2 × 10³ ◯ Example 3 No ◯ 3.5 × 10⁴ ◯Yes ◯ 1.5 × 10³ ◯ Example 4 No ◯ 1.1 × 10⁶ ◯ Yes ◯ 8.6 × 10⁴ ◯ Example 5No ◯ 2.9 × 10³ ◯ Yes ◯ 5.3 × 10² ◯ Example 6 No ◯ 9.2 × 10³ ◯ Yes ◯ 7.9× 10² ◯ Example 7 No ◯ 5.7 × 10⁵ ◯ Yes ◯ 2.5 × 10⁴ ◯ Example 8 No ◯ 6.4× 10⁴ ◯ Yes ◯ 3.9 × 10³ ◯ Example 9 No ◯ 1.8 × 10⁴ ◯ Yes ◯ 1.3 × 10³ ◯Example 10 No ◯ 4.2 × 10⁶ ◯ Yes ◯ 3.9 × 10⁵ ◯ Example 11 No ◯ 1.1 × 10⁶◯ Yes ◯ 2.1 × 10⁵ ◯ Example 12 No ◯ 3.2 × 10⁶ ◯ Yes ◯ 1.3 × 10⁵ ◯Example 13 No ◯ 6.4 × 10⁶ ◯ Yes ◯ 6.9 × 10⁵ ◯ Example 14 No ◯ 9.1 × 10⁵◯ Yes ◯ 1.5 × 10⁵ ◯ Example 15 No ◯ 5.2 × 10⁵ ◯ Yes ◯ 8.4 × 10⁴ ◯ Comp.Ex. 1 No X   >1 × 10¹² X Yes X   >1 × 10¹² X Comp. Ex. 2 No X   >1 ×10¹² X Yes X   >1 × 10¹² X Comp. Ex. 3 No X   >1 × 10¹² X No X   >1 ×10¹² X Comp. Ex. 4 No ◯ 1.5 × 10⁶ ◯ Yes ◯ 1.7 × 10⁶ ◯ Comp. Ex. 5 No ◯4.2 × 10⁷ ◯ Yes ◯ 4.2 × 10⁷ ◯

As is clear from Table 1, the solutions of the carbon nanotubecompositions of the present examples were uniformly dispersed ordissolved, and uniform coated films were formed. In addition, they alsodemonstrated low values of surface resistance. In particular, surfaceresistance values were able to be lowered even more by performingultrasonic treatment.

On the other hand, the carbon nanotube compositions of ComparativeExamples 1 to 3 demonstrated inferior surface resistance values andcoated film appearance. The electrical conductivity of ComparativeExamples 4 and 5 that used conducting composition 1 was not adequate.

INDUSTRIAL APPLICABILITY

The carbon nanotube composition of the present invention can be used bysimple coating methods such as coating, spraying, casting, and dippingfor various types of antistatic agents, capacitors, batteries, fuelcells and their polymer electrolyte membranes, electrode layers,catalyst layers, gas diffusion layers, separators and other members, EMIshields, chemical sensors, display elements, non-linear materials,preservatives, adhesives, fibers, spinning materials, antistaticcoatings, corrosion-resistant coatings, electrodeposition coatings,plating primers, conducting primers for electrostatic coating,electrical corrosion prevention and improvement of battery chargestorage.

In addition, a composite of the present invention is used as anindustrial packaging material for semiconductors, electrical applianceelectronic components and so forth, an antistatic film of electronicphotography and recording materials such as overhead projector film andslide film, for preventing accumulation of electrical charge of magneticrecording tape such as audio tape, video tape, computer tape and floppydisks, for LSI wiring of electronic devices, electron guns (sources) andelectrodes of field emission displays (FED), hydrogen storage agent, forprevention of accumulation of electrical charge on the surfaces of inputand display devices such as transparent touch panel, electroluminescentdisplay, and liquid crystal displays, and as light emitting materialsthat form transparent electrodes and organic electroluminescentelements, buffer materials, electron transfer materials, hole transfermaterials, fluorescent materials, thermal transfer sheets, transfersheets, thermal transfer imaging sheets and imaging sheets.

1. A carbon nanotube composition that contains a water solubleconducting polymer having an acidic group (a), a water or awater-containing organic solvent (b), carbon nanotubes (c), and a silanecoupling agent (g) represented by the following formula (1):

wherein in the formula (1) R²⁴², R²⁴³ and R²⁴⁴ respectively andindependently represent a group selected from the group consisting ofhydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms,linear or branched alkoxy group having 1 to 6 carbon atoms, amino group,acetyl group, phenyl group and halogen group, X represents thefollowing:

l and m represent values from 0 to 6, and Y represents a group selectedfrom the group consisting of a hydroxyl group, thiol group, amino group,epoxy group and epoxycyclohexyl group.